1. P. Breteque: Etudes sur le Gallium (Studies on Gallium, with a View to its Extraction during the Production of Alumina), Doctoral Thesis University Aix-Marseille, 1955, Imprimerie Vaudoise, Lausanne, Switzerland, 1956. (See Journal of Metals, Nov. 1956, pp. 1528–1529, for translation and summary).
2. M Beja: Method of Extracting Gallium Oxids from Aluminous Substances, US Patent 2,574,008, Nov. 1951.