American society of Aviation Artists
www.asaa-avart.org
Guild of Aviation Artists
www.gava.org.uk
Interesting Chinook website
www.chinook-helicopter.com
Information on Gustav Weisskopf,
pioneer fyiing machine builder.
www.gustavweisskopf.de
https://www.facebook.com/Alison-Boyle-Art-441427419268527/