Central Transportation Planning Staff (January 2004). "Chapter 5C: Service Expansion"(PDF). 2004 Program for Mass Transportation. Boston Metropolitan Planning Organization. Archived from the original(PDF) on February 16, 2008. Retrieved December 5, 2012.
Report on Improved Transportation Facilities in Boston. Division of Metropolitan Planning. December 1926. pp. 6, 7, 34, 35. hdl:2027/mdp.39015049422689.
Vanasse Hangen Brustlin, Inc (May 1, 2008). "Green Line Extension Project"(PDF). Massachusetts Executive Office of Transportation and Public Works. Archived from the original(PDF) on July 5, 2016.
Central Transportation Planning Staff (January 2004). "Chapter 5C: Service Expansion"(PDF). 2004 Program for Mass Transportation. Boston Metropolitan Planning Organization. Archived from the original(PDF) on February 16, 2008. Retrieved December 5, 2012.
Vanasse Hangen Brustlin, Inc (May 1, 2008). "Green Line Extension Project"(PDF). Massachusetts Executive Office of Transportation and Public Works. Archived from the original(PDF) on July 5, 2016.