@book{27625,
	author = {Hickok, William Orville,},
	title = {The minerals of Pennsylvania: Iron ores of Pennsylvania,},
	publisher = {Department of Internal Affairs, Topographic and Geologic Survey,},
	year = {1939.},
	address = {Harrisburg, Pa.,},
	note = {At head of title: Pennsylvania Geological survey, Fourth series}
}