"Aero Engines 1969". Flight International. Vol. 95, no. 3121. 2 January 1969. p. 27. Archived from the original on 17 April 2015. Retrieved 10 July 2015.
"Aero Engines 1969". Flight International. Vol. 95, no. 3121. 2 January 1969. p. 27. Archived from the original on 17 April 2015. Retrieved 10 July 2015.