@book{21363,
	author = {South Dakota. and Risk, Thomas M.},
	title = {Mathematics for secondary schools ...},
	publisher = {Fischer Printing Co.},
	year = {[1933]},
	series = {Course of study bulletin,},
	address = {Sioux Falls, S.D.,},
	note = {At head of title: State of South Dakota. Department of public instruction. Pierre.}
}