found: NUCMC data from Washington State Hist. Soc. for Cheyenne Airport Board collection, 1927-1932(name not given; records about aircraft design, maintenance, and service flights for planes belonging to Boeing Air Transport and Varney Air Lines)
found: United Airlines WWW Home page, Mar 13, 2000(Sept. 1974 United adopts a new two-word signature, United Airlines, marking the company's first departure from the three-word name adopted in 1931; UAL)
found: UAL Corporation. Annual report, 1974:p. 17 (United Airlines remained a wholly-owned subsidiary of UAL Inc. until UAL Inc. was reorganized into UAL Corporation on Dec. 22, 1993)
found: Wikipedia, Dec. 21, 2012:UAL Corporation (UAL Corporation controls United Airlines, UAL Corporation dissolved on Oct. 1, 2012 to form United Continental Holdings, Inc.)
found: Wikipedia, July 22, 2015(Continental Airlines merged into United Airlines on Mar. 3, 2012, UAL headquartered in Chicago)
