U.S. Navy sailors clean the aft 40 mm Bofors mounts during reactivation of the aircraft carrier USS <i>Princeton</i> (CV-37), in 1950.
U.S. Navy
<a rel="nofollow" class="external text" href="http://www.navy.mil/ah_online/department_arch.html">U.S. Navy All Hands magazine</a> <a rel="nofollow" class="external text" href="http://www.navy.mil/ah_online/archpdf/ah195010.pdf">October 1950</a>, p. 32.