@book{26938,
	author = {Condra, Geo. E. and Upp, Jerry Eli,},
	title = {Correlation of the Big Blue series in Nebraska,},
	publisher = {Printed by authority of the state of Nebraska,},
	year = {1931.},
	series = {Nebraska.  Geological survey.  Bulletin 6, second ser.},
	address = {[Lincoln]},
	note = {At head of title: University of Nebraska.}
}