1898 Map of Boston and vicinity showing tracks operated by the Boston Elevated Railway Co., surface lines, by Geo. H. Walker &amp; Co, from the Digital Commonwealth - commonwealth wd376720z. (<a rel="nofollow" class="external free" href="https://www.digitalcommonwealth.org/search/commonwealth:wd376720z">https://www.digitalcommonwealth.org/search/commonwealth:wd376720z</a>)
Geo. H. Walker &amp; Co,
Digital Commonwealth