A 1923 map of motor coach routes operated by the Washington Motor Coach System, including subsidiary Yakima Transit Company, jointly operated routes, and a new route applied for.
Motor Coach Association of Washington
<a rel="nofollow" class="external text" href="https://www.digitalarchives.wa.gov/Record/View/72D098B8B927168678983CD8C0E6B9FC">Washington State Archives</a>