used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Centre_of_Vision_(IA_centreofvision1909unse_6).pdf...
used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Centre_of_Vision_(IA_centreofvision1909unse_5).pdf...
used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Centre_of_Vision_(IA_centreofvision1909unse_1).pdf...