@book{18020,
	author = {Poldervaart, Arie,},
	title = {Crust of the earth :},
	publisher = {Geological Society of America,},
	year = {1955.},
	series = {Geological Society of America. Special paper},
	address = {New York :},
	note = {Papers prepared for the symposium held on October 14, 15 and 16, 1954, organized by the Dept. of Geology of Columbia University.}
}