California State Assembly. "An act to provide for a system of public streets and highways..."Fifty-seventh Session of the Legislature, 1st extraordinary session. Statutes of California. State of California. Ch. 11 p. 3798.: "Route 226 is from a point in the vicinity of the intersection of Webster Street and Santa Clara Avenue in Alameda to a point on Route 5 [I-580] in Oakland."
"Article 2 of Chapter 2 of Division 1". California Streets and Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
Federal Highway Administration (March 25, 2015). National Highway System: San Francisco–Oakland, CA(PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration. Retrieved July 22, 2017.
Natzke, Stefan; Neathery, Mike & Adderly, Kevin (June 20, 2012). "What is the National Highway System?". National Highway System. Washington, DC: Federal Highway Administration. Retrieved July 1, 2012.