journal video discussing historical impact event on Mars (页面存档备份,存于互联网档案馆) Aerial Explorations of Terrestrial Meteorite Craters (页面存档备份,存于互联网档案馆) All 172
September 2008 [17 October 2018]. Weber, Bruce. Don Ultang, Pioneer in Aerial Photography, Dies at 91. The New York Times. 26 September 2008 [17 October