@book{24833,
	author = {Geological Survey (U.S.) and Campbell, Marius R.},
	title = {Papers on the conservation of mineral resources /},
	publisher = {Govt. Print. Off.,},
	year = {1909.},
	series = {Bulletin 394},
	address = {Washington :},
	note = {Contents.- Coal fields of the United States, by M.R. Campbell and E.W. Parker.- Estimates of future coal production, by H. Gannett.- The petroleum resources of the United States, by D.T. Day.- Natural-gas resources of the United States, by D.T. Day.- Peat resources of the United States, exclusive of Alaska, by C.A. Davis.- Iron ores of the United States, by C.W. Hayes.- Resources of the United States in gold, silver, copper, lead, and zinc, by W. Lindgren.- The phosphate deposits of the United States, by F.B. Van Horn.- Mineral resources of Alaska, by A.H. Brooks.}
}