@book{28120,
	author = {Swineford, Ada, and Frye, John Chapman,},
	title = {Petrographic comparison of Pliocene and Pleistocene volcanic ash from western Kansas /},
	publisher = {[s.n.,},
	year = {1946]},
	series = {Kansas. State Geological Survey. Bulletin},
	address = {Lawrence, Kan. :},
	note = {Title page lacking.}
}