"Coupling Nuts". About Nuts, Materials, and Finishes. McMaster-Carr. Retrieved 26 March 2013. http://www.mcmaster.com/#hex-coupling-nuts/=m1m9ak
"Extension Nut / Coupling Nut". KisanEngineers.com. Kisan Engineers Machine Tools. Archived from the original on 27 December 2011. Retrieved 26 March 2013. https://web.archive.org/web/20111227100709/http://kisanengineers.com/nuts.html
American Railway Master Mechanics' Association (1922). Locomotive Cyclopedia of American Practice (sixth ed.). New York: Simmons-Boardman. p. 32. https://books.google.com/books?id=K4YMAwAAQBAJ&pg=PA32
Nunn, Richard V. (1982). Popular Mechanics Guide to Do-It-Yourself Materials. New York: Hearst Books. p. 54. ISBN 978-0-87851-150-1. 978-0-87851-150-1
Olin, L.; Stanland, A.; Allard, F. (1987). "Fiber Optic Hull Penetrators for Submarines". In O'Donnell-Leach, Karen (ed.). Military Applications of Fiber Optics. Fiber Optics Reprint Series Volume 14. Brighton, Massachusetts: Information Gatekeepers Inc. pp. 58–63, page 61.
"The Use of Two Nuts to Prevent Self Loosening of Fasteners". www.boltscience.com. Retrieved 2024-01-17. https://www.boltscience.com/pages/twonuts.htm