<a href="https://en.wikipedia.org/wiki/American_Institute_of_Architects" class="extiw" title="en:American Institute of Architects">American Institute of Architects</a> Centennial - 3-cent 1957 issue U.S. stamp.
Bureau of Engraving and Printing. Designed by Robert J. Schultz.
U.S. Postal Service; National Postal Museum: <a rel="nofollow" class="external text" href="http://arago.si.edu/category_2029411.html">Architects Issue</a>