Diagram of a Boston Elevated Railway Articulated #1 car, made from two 1890s-built 20-foot trams, in 1912
Unknown author<span style="display: none;">Unknown author</span>
1912
<a rel="nofollow" class="external text" href="https://books.google.com/books/about/Electric_Railway_Journal.html?id=iY5MAAAAYAAJ">Electric Railway Journal, October 5, 1912</a>