Smith, Richard (1983). "The Intercontinental Airliner and the Essence of Airplane Performance 1929–1939". Technology and Culture. 24 (3): 428–449. doi:10.2307/3104760. JSTOR3104760. S2CID111745609.
Ewer, Peter (2007). "A Gentlemen's Club in the Clouds: Re-assessing the Empire Air Mail Scheme 1933–1939". Journal of Transport History. 28 (1). doi:10.7227/TJTH.28.1.6. S2CID144016759.
jstor.org
Smith, Richard (1983). "The Intercontinental Airliner and the Essence of Airplane Performance 1929–1939". Technology and Culture. 24 (3): 428–449. doi:10.2307/3104760. JSTOR3104760. S2CID111745609.
semanticscholar.org
api.semanticscholar.org
Smith, Richard (1983). "The Intercontinental Airliner and the Essence of Airplane Performance 1929–1939". Technology and Culture. 24 (3): 428–449. doi:10.2307/3104760. JSTOR3104760. S2CID111745609.
Ewer, Peter (2007). "A Gentlemen's Club in the Clouds: Re-assessing the Empire Air Mail Scheme 1933–1939". Journal of Transport History. 28 (1). doi:10.7227/TJTH.28.1.6. S2CID144016759.