Lewis, William E. 18. Through the Heartland on U.S. 20: Massachusetts: Volume I: A Historical Travel Guide. Publish America. March 2007 [2018-06-02]. ISBN 9781462624591. (原始内容存档于2020-07-27).
Firsts. springfield375.org. Springfield 375. [2012-09-29]. (原始内容存档于2013-05-21).
Lewis, William E. 18. Through the Heartland on U.S. 20: Massachusetts: Volume I: A Historical Travel Guide. Publish America. March 2007 [2018-06-02]. ISBN 9781462624591. (原始内容存档于2020-07-27).