@book{28434,
	author = {Joubert, G. K.},
	title = {Tungsten ores in South Africa with special reference to Namaqualand and the Orange River.},
	publisher = {Govt. Printer,},
	year = {1941.},
	series = {South Africa. Dept. of Mines. Geological series. Bulletin},
	address = {Pretoria,}
}