@book{27585,
	author = {Pennsylvania. and Willard, Bradford,},
	title = {The Devonian of Pennsylvania :},
	publisher = {Dept. of internatl affairs, Topographic and geologic survey,},
	year = {1939.},
	address = {Harrisburg, Pa. :},
	note = {At head of title: Pennsylvania Geological Survey, Fourth series.}
}