80-G-40885:  Building PBM’s at the Glenn L. Martin Plant near Baltimore, Maryland.   Highly polished convex plexi-glass domes of machine gun turrets.  TR-2609, 1943.   U.S. Navy Official U.S. Navy Photograph, now in the collections of the National Archives.  (2016/12/20).
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/127906254@N06">National Museum of the U.S. Navy</a>
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