Joe Baugher: Curtiss XP-31. joebaugher.com, 2003-07-01. [dostęp 2016-02-10].
worldcat.org
Walter J. Boyne. Curtiss built well but not too wisely with its XP-31 Swift, a sleek-looking but overweight fighter. „Aviation History”. 13 (6), 2003-07-01. ISSN1076-8858.