@book{30478,
	author = {Marks, John L.},
	title = {Teaching elementary school mathematics for understanding},
	publisher = {McGraw-Hill},
	year = {[1975]},
	address = {New York},
	edition = {4th ed.},
	note = {First ed. published in 1958 under title: Teaching arithmetic for understanding. Previous editions by J. L. Marks, C. R. Purdy, and L. B. Kinney.}
}