@book{24950,
	author = {Marshall, R. B.},
	title = {Results of spirit leveling in Delaware, District of Columbia, Maryland, and Virginia, 1896 to 1909, inclusive.},
	publisher = {Govt. Print. Off.,},
	year = {1910.},
	series = {U.S. Geological survey. Bulletin},
	address = {Washington,},
	note = {Issued also as House doc. no. 1015, 61st Cong., 3d sess.}
}