@book{27820,
	author = {Grim, Ralph E.},
	title = {Modern concepts of clay materials,},
	year = {1942.},
	address = {Urbana, Illinois,},
	note = {At head of title: State of Illinois, Dwight H. Green, Governor. Department of Registration and Education, Frank G. Thompson, Director. Division of the State Geological Survey, M. M. Leighton, Chief, Urbana.}
}