1. The Plant List (2019) Washingtonia. 16 May 2019.
http://www.theplantlist.org/tpl1.1/search?q=Washingtonia
2. Johnson DV (1998) Non-wood forest products 10: tropical palms. Food and Agriculture Organization of the United States (FAO), Rome
3. Bomhard ML (1950) Palm trees in the United States. Agriculture information bulletin, vol 22. U.S. Department of Agriculture, Forest Service, Washington, DC, p 26
4. Sudworth GB (1908) Forest trees of the Pacific slope. U.S. Department of Agriculture. Forest Service, Washington, DC, p 441
5. Jepson WL (1910) The silva of California, vol 2. University of California Press, Berkeley, p 283