Transcribed from Wright Aeronautical documents by Robert J. Neal T; available from the Aircraft Engine Historical Society's reference page. Citation title of source Summary of Wright Engine Shipments: 1920 to 1963 url of source http://enginehistory.org/Wright/WrightProd.pdf format PDF accessdate December 10, 2009 ↑ Aircraft Engines, retrieved 2008-09-11 .