"Chapter 45: Resolve providing for an investigation by the Division of Metropolitan Planning relative to the extension and development of rapid transit service in Boston, Somerville and surrounding cities and towns". Acts and resolves passed by the General Court of Massachusetts in the year 1924. May 24, 1924. pp. 602–603 – via Internet Archive.
"Executive Summary"(PDF). Program of Mass Transportation. Boston Regional Metropolitan Planning Organization. January 2004. p. 2-9. Archived from the original(PDF) on February 20, 2012.
Report on Improved Transportation Facilities in Boston. Division of Metropolitan Planning. December 1926. hdl:2027/mdp.39015049422689.
Sindel, David A. (June 2017). Strategies for meeting future capacity needs on the light rail MBTA Green Line (Thesis). Massachusetts Institute of Technology. hdl:1721.1/111263.
mbta.com
mbta.com
"Alerts: Subway". Massachusetts Bay Transportation Authority. October 14, 2021. Archived from the original on October 14, 2021.
"Alerts: Subway". Massachusetts Bay Transportation Authority. October 14, 2021. Archived from the original on October 14, 2021.
"Executive Summary"(PDF). Program of Mass Transportation. Boston Regional Metropolitan Planning Organization. January 2004. p. 2-9. Archived from the original(PDF) on February 20, 2012.
"Subway Map"(PDF). Massachusetts Bay Transportation Authority. 2001. Archived from the original(PDF) on July 1, 2001.