@book{25500,
	author = {Grout, Frank F. and Soper, Edgar Kirke, and Geological Survey (U.S.)},
	title = {Preliminary report on the clays and shales of Minnesota,},
	publisher = {The University of Minnesota,},
	year = {1914.},
	series = {Minnesota. Geological survey.  Bulletin 11},
	address = {Minneapolis,},
	note = {At head of title: The University of Minnesota.}
}