Dubois, Thierry; Huber, Mark (February 2012). "New Rotorcraft 2012"(PDF). Aviation International News. Archived from the original(PDF) on 9 June 2016. Retrieved 31 March 2012. ...is now believed to have soared to $30 million.
Fortenbaugh, Robert; Hopkins, Roy II; King, David (2004). "BA609 First Flight VSTOL Handling Qualities". American Helicopter Society 60th Annual Forum. The Vertical Flight Society.
Dubois, Thierry; Huber, Mark (February 2012). "New Rotorcraft 2012"(PDF). Aviation International News. Archived from the original(PDF) on 9 June 2016. Retrieved 31 March 2012. ...is now believed to have soared to $30 million.