From Citizendium, the Citizens' Compendium
- Please sort and annotate in a user-friendly manner. For formatting, consider using automated reference wikification.
- Bassett, Gordon C. (1991). "Modeling the 'Beep'." The Santa Fe Modeler 14 (1) 8–14.
- The "Beep": Santa Fe's SWBLW. Werkema, Evan. Retrieved on August 15, 2013. Includes background information and a photo gallery.
- The History of EMD Diesel Engines. Pacific Southwest Railway Museum. Archived from the original on 13 January 2006. Retrieved on December 14, 2005.
- Pinkepank, Jerry (1973). The Second Diesel Spotter's Guide. Kalmbach Publishing Co., Milwaukee, WI. ISBN 978-0890240267.