@book{25254,
	author = {Knopf, Adolph,},
	title = {Ore deposits of the Helena mining region, Montana /},
	publisher = {Govt. Print. Off.,},
	year = {1913.},
	series = {U.S. Geological survey. Bulletin 527},
	address = {Washington,},
	note = {Some of the plates printed on both sides of leaf.}
}