@book{27197,
	author = {Leith, C. K. and Lund, Richard Jacob,},
	title = {Pre-Cambrian rocks of the Lake Superior Region;},
	publisher = {U.S. Govt. Print. Off.,},
	year = {1935.},
	address = {Washington :},
	note = {At head of title: United States Department of the Interior.}
}