@book{18453,
	author = {Ahrens, L. H. and Unesco.},
	title = {Origin and distribution of the elements /},
	publisher = {Pergamon Press,},
	year = {1968.},
	series = {International series of monographs in earth sciences, v. 30},
	address = {Oxford ;},
	edition = {1st ed.]},
	note = {Papers in English, French, or German.}
}