Posted in diplodocids

In search of rearing mounted sauropod skeletons

I’m pretty sure that our old friend the AMNH Barosaurus was the first sauropod skeleton even mounted in a rearing pose.

Taylor and Wedel 2016:Figure 1. Mounted cast skeleton of Barosaurus referred specimen AMNH 6341, in the entrance hall of the American Museum of Natural History. Homo sapiens (MPT) for scale. Photograph by MJW.

(Does anyone know of an earlier one? That would be fascinating!)

But what other mounted sauropods have been placed in a rearing posture, with both forefeet off the ground? I know of four others. First, the rearing Diplodocus at the Museum of Science and Innovation in Tampa, Florida, that we discussed in detail in Taylor et al. (2023:80–82):

Taylor et al. 2023:Figure 10. Double Diplodocus mount at the Museum of Science and Industry (MOSI), Tampa, Florida. Both individuals are identical, having been cast from the molds made by Dinolab from the concrete Diplodocus of Vernal. Photograph by Anthony Pelaez, taken between 1997 and 2017.

Strangely enough, the other three are all individuals of Camarasaurus, an ugly four-square sauropod whose centre of gravity was well forward of the acetabulum in normal posture, and which would have found rearing much more difficult than in diplodocids. My guess is that’s just because Camarasaurus is so abundant that there are a lot of mounted skeletons out there, and some have been mounted in rearing postures because, well, why not?

Here is one from the Wyoming Dinosaur Centre in Thermopolis:

Camarasaurus skeleton from the BS (Beside Sauropod) quarry, on display at the Wyoming Dinosaur Center. Photograph by CryolophosaurusEllioti, CC By. https://commons.wikimedia.org/wiki/File:WDC_-_Camarasaurus_skeleton.jpg

(I can’t find a good photo of this mount from the front or the side: if anyone can, please let me know in the comments.)

The next is in the US National Museum (USNM), otherwise known as the NMNH, otherwise known as the Smithsonian. It’s on the right of this photo:

Rearing Camarasaurus (right of photo, the smaller of the two sauropods) at the USNM/NMNH/Smithsonian. Photo by Ben Miller. https://sauropods.win/@extinctmonsters/109293854660129716

And finally, as I was putting this post together, I stumbled across this mount at the Naturalis Biodiversity Center in Leiden, the Netherlands:

Yet another rearing Camarasaurus, at the Naturalis Biodiversity Center in Leiden, the Netherlands. Photo by thedogg, CC By-SA. https://commons.wikimedia.org/wiki/File:WLANL_-_thedogg_-_Camarasaurus_(2).jpg

I know nothing about this one, and would welcome any details.

In fact, I don’t know much about any of the three rearing camarasaurs. Can anyone tell me, for example, when they went up? And whether the AMNH Barosaurus was a conscious inspiration?

And the $64,000 question: does anyone know of other rearing sauropod mounts?

References

 

doi:10.59350/qg664-9be62

Tutorial 48: my museum collections kit

I was on the road for most of August, September, and October, and in particular I made a ton of museum collections visits. When I visit a museum collection, I bring a specific set of gear that helps me get the photos, notes, and measurements that I want. All of this is YMMV — I’m not trying to predict what will work best for you, but to explain what has worked for me, and why. I’m reasonably happy with my current setup, but even after 28 years of museum visits, I’m still finding ways to improve it. Hence this post, which will hopefully serve as a vehicle for sharing tips and tricks.

A word about my program when I visit a collection, because not everyone needs or wants to do things my way. The closest museums with extensive sauropod collections are states away from where I live and work. If I’m in those collections at all, I’m traveling, and therefore on the clock. Time in collections is a zero-sum game: if I have the time to take 20 pages of notes, that could be 4 pages of notes of each of 5 specimens, 2 pages on 10, 1 page on 20, half a page on 40, etc. In practice, I usually make expansive notes early in the visit, one or two spreads per specimen with detailed sketches and exhaustive measurements of the most publication-worthy elements. I grade toward brevity over the course of the visit, and end with a mad desperate rush, throwing in crude sketches and rudimentary notes on as many newly-discovered (by me) specimens as possible. My collections visits are Discovery Time and Gathering Time, trying to get all the measurements and photographs I’ll want for the next year, or five, or forever. And, to the extent that I can suppress them, not Analysis Time or Graphing Time or Writing Time — I can do those things after hours and in my office back home, IF and only if I’ve spent my collections time efficiently gathering all the information I’ll need later.

The very first thing I do in any collection is a walking survey, to make sure I know roughly what specimens the collection contains and where to find them. For a sufficiently large collection — or even a single cabinet with 10 drawers of good stuff — I may draw a map in my notebook, on which I can note things I want to come back and document, and add new things as I find them.

Enough preamble, on to the gear. The first two or three entries here are in strict priority order, and after that things get very fuzzy and approximate.

1. Research Notebook

Seems obvious, right? Write stuff down, make sketches, capture the info that will be difficult or impossible to recapture later from photos. I have encountered people who don’t take a physical notebook, just a laptop or tablet, and take all their notes digitally. If that works for you, may a thousand gardens grow. For me, sketching is a fundamental activity — for fixing morphology in my mind, disciplining myself to see the whole object and its parts, creating a template on which to take further explanatory notes, and capturing the caveats, stray ideas, and odd connections that surround each specimen in a quantum fuzz in my mind (temporarily in my mind, hence the need for external capture). I also write priority lists in advance of specimens to document each day, and then cross them off, add new ones, and strike out duds with wild abandon in the heat of data collection.

I do a few specific things to increase the usefulness of my notebooks:

– Label the spines and covers with the notebook titles and years. These things live on the shelf directly over my desk, and I pull them down and rifle through them constantly. I also have notebooks for university service (committees, student advising, and so on), astronomical observations, and personal journaling, so “Research” is a useful tag for me.

– Number the pages, if they’re not already numbered, use the books chronologically from front to back, and create the table of contents retrospectively as I go — a tip I got from the Bullet Journal method.

– Paste a small envelope inside the back cover, if a pouch is not already built in, to hold all kinds of ephemera — index cards, scale bars, a bandage (just in case), stickers I acquire along the way, etc.

– Affix a section of measuring tape to the outer edge of the front or back cover. I got this tip from the naturalist John Muir Laws, whose Laws Guide to Nature Drawing and Journaling is wonderfully useful and inspiring (UPDATE: that book is now covered in its own post, here). The scale-bar-permanently-affixed-to-research-notebook has been a game-changer for me. Do you know how many times I’ve accidentally left a scale bar on a museum shelf, and then gotten to my next stop and had to borrow or fabricate one? I myself lost count long ago. But never again. If I’m in a hurry, small specimens go straight onto the notebook to be photographed, like the baby apatosaurine tibia above, and the notebook itself goes into the frame with large specimens. (This comes up again — if possible, and it’s almost always possible, put the specimen label in the photo with the specimen. No reason not to, and sometimes a lifesaver later on.)

Behold the thinness of the eminently pocketable IKEA paper tape. Folding instructions, because this seems to bedevil some folks: hold up one end, fold in half by grabbing the other end and bring it up in front, then do that three more times. Finished product is 65mm long, 25.4mm wide, and about 1mm thick when folded crisply and left under a heavy book overnight.

2. Measuring tapes

I find the flexible kind much more convenient and useful than retractable metal tape measures. I like the 1-2mm thick plastic type used by tailors and fabric sellers, because they have just enough inertia to stay where I put them, or drop in a predictable fashion when draped over something sufficiently large, as when measuring midshaft circumference of a long bone.

I LOVE the little plasticized paper tapes that hang on racks, free for the taking, near the entrances of IKEA stores. I tear them off by the dozen when I go to IKEA, cram them in my pockets, fold them flat when I get home, and stash them everywhere, including in my wallet. A few specific reasons they’re great:

– Folded flat, they’re about the thickness of a credit card, so there’s just no reason to be without one. I usually have one in my wallet, another in the envelope at the back of my research notebook, a couple more stashed in my luggage, a couple more stashed in my car, desk, tookbox, nightstand, etc.

– I can write on them. Especially handy if:

– I’ve torn off a section to serve as an impromptu scale bar. Which I never hesitate to do, because they’re free and I have dozens waiting in my toolbox and desk drawers at any one time. Torn off bits also make good bookmarks, classier, more cerebral, and less implicitly gross than the traditional folded square of toilet paper.

– I give them away to folks I’m traveling with, or that I meet in my travels, and they’re usually well-received.

I would NOT have figured out all these laminae if I hadn’t had a way to make them stand out.

3. Writing instruments in various colors

Up until about 2018 my notebooks were always monochrome pen or pencil. Then I realized that color is an extremely helpful differentiator for Future Matt, so now I highlight and color-annotate willy-nilly.

4. Calipers

I borrowed the digital calipers from Colin Boisvert to get the photo up top, having forgotten my own at home. As a sauropod worker, I don’t need sub-millimeter accuracy all the time. But digital calipers have three exceedingly useful functions: measuring the thickness of very thin laminae and bony septa; measuring the internal dimensions of small fossae and foramina; and measuring the depth of fossae and of concave articular surfaces. I also have a little titanium caliper on a lanyard that goes with me most places.

5. Small brush on a carabiner

This is the newest addition to the kit. I got the idea from Matthew Mossbrucker at the Morrison Museum in Morrison, Colorado. Colin and I visited him in September, immediately before our week-long stint in the collections at Dinosaur Journey. Matthew keeps a little brush carabinered to his belt at all times, and the utility was so instantly obvious that when Colin and I rolled into Fruita later that same day, I went to the hardware store and got my own. Cheap, weighs nothing, clips to anything, compact enough to cram in a pocket, good for lab and field alike. Genius!

6. Scale bar

Yes, I have my scale-bar-enhanced research notebook and my hoarder stash of IKEA paper tapes, but good old-fashioned scale bars are still useful, and I use them constantly. And lose them constantly, hence my multiple redundant backup mechanisms.

(Aside: I can’t explain why I hold onto some objects like grim death, but let others fall through my fingers like sand grains. I’ve only lost one notebook of any kind in my entire life — set it on top of the car while packing and then drove off [grrrr] — so I have no problem investing in nice notebooks and treating them like permanent fixtures. But I can’t hang onto pens and scale bars to save my life, hence my having gravitated to Bic sticks and IKEA paper tapes.)

7. Index cards

I try to get as much information into each photograph as possible. Ideally alongside the specimen I will have:

– a scale bar at the appropriate depth of field;

– the specimen tag with the number, locality, and other pertinent info;

– my notebook open to my sketch of the specimen, for easy correlation later (I don’t do this for every single view, just the ones that I think are particularly publication-worthy, or have info I’m likely to forget later);

– anything else I might want — serial position, anatomical directions, whether the photo is part of an anaglyph pair, and so on — written on an index card, which being a standard size will itself serve as an alternate/backup scale bar.

8. Pencil case

To hold all the smaller fiddly bits you see in the photo up top. I can’t now fathom why, but I resisted getting one of these for a loooong time. I was young and foolish then. Pretty useful all the time, absolutely clutch when it’s 4:58 pm and I’m throwing stuff in bags, caught between the Scylla of working as late as possible and the Charybdis of wanting to be polite to whatever kind, patient person is facilitating my visit. That is also when the pocket in the back of the notebook comes in especially handy.

Headlamp in action, casting low-angle light on a pneumatic fossa on the tuberculum of this sauropod rib. Note also the scale bar, elevated on a specimen box to be the same depth of field, and the notebook open to my sketch of the specimen.

9. Artificial lighting

This was another very late discovery for me — I don’t think I was regularly bringing my own lights prior to 2018. For me, portable, rechargeable lighting is useful in many circumstances and absolutely critical in two: casting low-angle light to pick out subtle pneumatic features, as in the photo above, and lighting up big specimens that I don’t have the time, energy, or space to pull off the shelves, as in the photo below.

I’m particularly taken with the big orange fan/light combo. It charges using a USB-C cable, has four settings for fan speed (handy when it’s hot, humid, or just oppressively still) and three for light intensity, a rotating hook that folds flat, and a USB power-out socket for charging phones, headlamps, fitness trackers, and what have you. I use it practically every day whether I’m on the road or not.

Magnetic flashlight hanging from steel shelving to illuminate Camarasaurus cervical vertebrae in the Utah Field House collections.

Whether it’s a hook or a magnet, some kind of mechanism for suspending a light at odd heights and angles is super useful. I usually have a strong flashlight with an integral seat-belt cutter and window-smasher in the door pocket of my car, and its magnetic base makes it omnidirectionally functional in collections spaces, which are usually liberally supplied with steel in the form of shelving and cabinets.

Haplocanthosaurus CM 879 caudal 2 in left lateral view, with rolled-up paper neural canal visualizer and scale-bar-stuck-to-flashlight.

Sometimes I use a bit of blue tack to stick a scale bar to a flashlight, to create a free-standing, truly vertical scale bar that I can rapidly place at different distances from the camera. Beats leaning the scale bar against a stack of empty specimen boxes or a block of ethofoam (which in turn beats nothing at all).

What else?

USUALLY — Laptop

Not for recording notes or measurements — all of that goes into the notebook, which I scan and upload new stuff from every evening. Mostly for displaying PDFs of descriptive monographs, and hugely useful in that regard.

MAYBE — Monographs

When I have the freedom (= baggage allowance) to do so, I find it handy to bring hardcopies of descriptive monographs, both for quick reference and so I can photograph specimens alongside the illustrations. Doesn’t even have to be the same specimens, just comparable elements. In the photo above, MWC 7257, a partial sacral centrum of Allosaurus from the Mygatt-Moore Quarry, is sitting next to a plate from Madsen (1976), illustrating the same vertebra in a specimen from Cleveland Lloyd Dinosaur Quarry. Thanks to Colin Boisvert for bringing the specimen to my attention — I’ve got a longstanding thing for sacrals — and for loaning me his copy of Madsen (1976) for this photo.

OUT — Camera and tripod

I suspect that some folks will shake their heads in mute horror, but after a couple of decades of lugging dedicated cameras and tripods everywhere, I stopped. For the past few years I’ve been rolling with just my phone, which is objectively better than any dedicated camera I owned for the first half of my career. Sometimes I brace it in an ad hoc fashion against a chair or shelf or cabinet, but mostly I just shoot freehand. For my purposes, it does fine, and any minor improvements in field curvature or whatever that I’d get from a dedicated camera don’t outweigh the logistical hassle. Again: YMMV!

Over to you

So, that’s what I roll with right now. It was different six months ago, and will almost certainly be a little different six months hence, hopefully as a result of people responding to this post. With all that said: what’s in your kit?

P.S. Many thanks to Matthew Mossbrucker and Julia McHugh for their hospitality and assistance in their collections, and to Colin Boisvert for being such a great travel companion, research sounding board, and generous loaner-of-things-I’d-forgotten. The Wedel-Boisvert Morrisonpocalypse 2025 deserves more blogging.

 

doi:10.59350/c21vr-f8727

Get your name into the permanent scientific record!

Just a quick update on the crowd-funding effort to publish the new diplodocoid volume as open-access papers at Palaeontologia Electronica.

Van der Linden et al. 2024:Figure 6. Cervical vertebra 13 of Ardetosaurus viator MAB011899. CV13 is shown in A) ventral, B) dorsal, C) left lateral, D) right lateral, E) posterior, and F) anterior view. A close up of the white box in F is provided of the accessory laminae in the SPRF, shown in anterodorsal view. White shaded areas indicate reconstructed parts. The left cervical rib loop was obscured in ventral view for support and therefore roughly outlined here. White dotted lines in A indicate the remnants of the ventral keel. 1 indicates the triangular projections on the diapophysis. Abbreviations: al, accessory lamina; CPRL, centroprezygapophyseal lamina; epi, epipophysis; pap, parapophysis; PCDL, posterior centrodiapophyseal lamina; pre, pre-epipophysis; PRSL, prespinal lamina; pvf, posteroventral flange; SPOL, spinopostzygapophyseal lamina; SPRL, spinoprezygapophyseal lamina; TPOL, interpostzygapophyseal lamina.

The drive now contains an offer that maybe it should have included from the start: “We promise to mention the names of the backers in the acknowledgements of at least one upcoming paper, if this campaign is successful.”

I don’t know how big an incentive this will feel to different people. But I remember the thrill the first time my own name appeared in the scientific record, in the acknowledgements of the “Angloposeidon” paper (Naish et al. 2004), and I hope it will do the same for some of you.

So if you’d like to contribute, and become the envy of your friends and family by appearing in the scientific record as a sponsor of sauropod palaeontology, get yourself over to the crowdfunding page!

References

 

doi:10.59350/pr6q9-6rr58

Want to help fund the free publication of sauropod science? Now’s your chance!

Anyone who’s been reading this blog for a while knows that Matt and I are both all in on open access. What is the point of “publishing” something that not everyone can read? We always want our work to be available to the widest possible audience, so it’s a no-brainer that we won’t let it moulder behind a paywall.

But the process of scholarly publication does cost money. Nowhere near as much as commercial publishers charge, sure, but there is an irreducible cost which has to be paid somehow.

And now, here comes Diplodocoidea (Dinosauria, Sauropoda): Systematics, Phylogeny, Biogeography!

This is the snappy title of a “virtual edited volume” on Diplodocoids, which is being published a chapter at a time at the venerable open-access journal Palaeontologia Electronica (PE for short). Each chapter comes out as soon as it’s ready, and you’ve probably already seen the first two:

Two more chapters have already been accepted and are in press; and a fifth is in review. There are plenty more in preparation, including at least one more new diplodocoid. A link to each paper will appear in the Table of Contents page, so that page will always be an index to all the available content.

To cover their costs for this volume, PE needs $3000. That comes out crazy cheap — we’re looking at a double-digit number of papers, so the cost to make each one freely available to the whole world in perpetuity is less than $300.

To raise this money, the group has kicked off a crowdfunding effort. It has a little under a month to raise the necessary $3000, and as I write this it’s 20% of the way to that goal. If you can afford to chip in, please do get yourself over there and make a contribution. You’ll have the satisfaction of knowing that you helped increase the world’s access to knowledge of diplodocoids.

 

doi:10.59350/wnkxe-b8330

My first palaeo paper is 20 years old today!

One of the things that comes up over and over — on this blog, at conferences like DinoCon, on Q&A websites — is how to become a palaeontologist. As I’ve said before (at some length) the way to become a published palaeontologist is to publish papers about palaeontology.

But that’s a very general, broad-stroke recipe, and some details might be interesting. Today is 20th anniversity of my own first published palaeontology paper, and I’m going to say a little bit about how it came about. Maybe there are broader lessons to be learned.

Taylor and Naish 2005: Figure 1. Relationships between sauropods showing successive outgroups to Diplodocus. Includes basal sauropodomorphs (represented by Plateosaurus), Macronaria (represented by Saltasaurus) and Diplodocoidea (represented by all other genera named in the figure). The numbers 1, 2 and 3 indicate possible positions for Haplocanthosaurus, discussed in the text. The letters A to L indicate nodes and stems in this phylogeny, the names and definitions of which are discussed in the text.

I started reading the old Dinosaur Mailing List (now the Dinosaur Mailing Group) around 2000, and that led me to the published literature.

By 2003 I’d read enough papers to have a sense of what was good and what was not. One day (on a transatlantic flight for my day-job, if memory serves), I read one particular paper that was so obviously flawed, I thought even I could do better. So it was in my mind that writing a paper might not be an unrealistic goal. But I had no particular topic in mind, so the idea just sat quietly in the back of my mind, percolating.

Then, on 6 October 2003, Matt Wedel asked me a fateful question in an email: “Do you know how dino diversity breaks down by clade, i.e. how many genera or spp. each of theropods, sauropodomorphs, and the various  ornithischian groups?” I’m a computer programmer by trade, so my immediate impulse was to write a program to compute this. I replied: “the best I could do would be to download the raw XML data from Mike Keesey’s [now sadly defunct] Dinosauricon web-site and analyse that by clade”.

So I did. Having come that far, there were other obvious analyses to run on the data. That project grew into a paper with all those different analyses of the relevant data, and by the time I was ready to submit it I’d replaced the original data-set with one drawn from Don Glut’s Dinosaurs: The Encyclopaedia and its supplements. (Fiona read the relevant data out to me and I typed it in.) Confident that this paper was going to be my debut, and I sent three double-spaced printed copies off to Acta Palaeontologica Polonica on 24 October 2024. A couple of weeks later I got a letter back in the post telling me it had been rejected without review. (As of 2014, the manuscript of that paper is available as a “preprint”.)

So that crashed and burned. But once I’d got into the process of writing it, I started feeling like the kind of person who wrote papers, so I was open to starting other projects.

In May 2004, I’d started to feel a bit itchy about the way some papers used the name Diplodocoidea and other used Diplodocimorpha, and about the way these two names had several similar-but-not-identical definitions. At this point I had no intention of writing that up, I was just chasing down the definitions for my own interest. There’s an archived copy of the Dinosaur Mailing List thread for those who want the gritty detail.

Among those who weighed in on the thread was Darren Naish, and he and I somehow arrived at the idea that this little nomenclatural question was complex enough, and touched on enough other names, that it was worth writing up. I started a file just called “text” on 3 June, which got promoted to an OpenOffice document on 7 September, shortly before the Leicester SVPCA. On the train to Leicester, I met up with Darren and we went through the manuscript together, figuring out what needing moving around, what was missing, what was redundant, and so on.

When I got home after the conference (where I gave a talk on the diversity work that I thought was still alive), I revised the paper and Darren and I batted versions back and forth for a while. Darren also contributed the illustration above, as I’d not learned to use a graphics editor at this point.

On 10 October, we posted it to the Journal of Paleontology (again as hard copy). It came back in late January (yes, three and a half months later), rejected with, I thought, a couple of fairly harsh reviews.

In my memory, we turned it around pretty quickly for submission elsewhere, but my records show it was actually more than four months before we sent a somewhat revised version to PaleoBios — this time by email, proving that Modern Times began at some point between October 2004 and May 2005.

This time we lucked out on the reviewers[1]: we got Matt (who at that point of course had never published with either Darren or me, so there was no evident conflict of interests), and Jerry Harris (who is the best, most pedantic and constructive of reviewers). The paper was accepted on 5 July, subject to some small changes. We made these, received, read and corrected page proofs, and the paper was published on 15 September 2005 — twenty years ago to the day. You are welcome to read it (Taylor and Naish 2005): PaleoBios was then a print-only paper, but I put the PDF on my own website, as I do with all my papers.

[1] Yes, I do think it’s honest to say that who you get allocated as a reviewer makes a big difference. Neither Matt not Jerry is a pushover — they had their criticisms. But both of them approach the task of review with the primary attitude of, what would make this paper really good? Whereas certain other reviewers see their jobs much more as being gatekeepers.

It’s a short paper — seven pages in total, including a half-page illustration, a full-page table and two pages of references. We didn’t expect it to set the world alight, just to be helpful to a few specialists who wanted certainty about the same nomenclatural issue that had bothered me at the outset. But I’ve been pleasantly surprised: according to Google Scholar it’s been cited 43 times, and it seems still to be slowly but surely racking up the citations. (It is just outside my top ten most-cited papers, by a single point.)

What have we learned?

By the time I came to write the early drafts of what became Taylor and Naish 2005, I had (I now realise) a lot of useful experience behind me:

  • I’d learned to write good prose.
  • I’d come roughly up to speed with the current state of dinosaur palaeontology, thanks to the Dinosaur Mailing List and the various books I’d read.
  • I’d got used to reading the technical literature, and had a feel for what makes a good paper.
  • I’d accumulated enough self-confidence to think, heck, why shouldn’t I make a contribution?
  • I’d made contact with useful collaborators: not just Darren, who became my co-author, but Matt, who asked me the question that provoked my first submitted paper.
  • I’d had the experience of submitting and being rejected, so that when it later happened with the paper in question it wasn’t crushing.
  • I’d got interested in a specific, small problem, which I wanted to solve for myself.
  • I was part of a community (the DML again) where I could spray questions around and get useful references to relevant literature.

These are all useful things to have on your side, and if you want to be a palaeontologist, I encourage you to find and develop analogous advantages. (Mostly: do a lot of reading, a lot of writing, and plant yourself in a community.)

Then in putting this particular paper together, two more things went my way:

  • I got some in-person time with my principal collaborator at just the right time.
  • On the second roll of the dice, we got sympathetic reviewers.

You could say I was lucky with these last two things; but then to some extent you make your own good-luck events by keeping on rolling the dice until they come up sixes. Keep rolling the dice.

As we come to the end of a longish post, I hope I’ve demystified the process a bit. What you should take away from all this is that there’s nothing particularly special about me. What I’ve done in the world of palaeontology, others can do. A surprising amount of it comes down to just keeping of doing the work.

References

  • Taylor, Michael P., and Darren Naish. 2005. The Phylogenetic Taxonomy of Diplodocoidea (Dinosauria: Sauropoda). PaleoBios 25(2):1-7.

 

doi:10.59350/mvc28-0tx44