Pirie, G. H. (1990). "Aviation, Apartheid and Sanctions: Air Transport to and from South Africa,1945—1989". GeoJournal. 22 (3): 231–40. doi:10.1007/BF00192821. S2CID154691990.
Pirie, G. H. (1990). "Aviation, Apartheid and Sanctions: Air Transport to and from South Africa,1945—1989". GeoJournal. 22 (3): 231–40. doi:10.1007/BF00192821. S2CID154691990.