Otto, Henry John Principles of elementary education. - Rev. ed. [by] Henry J. Otto, Hazel Floyd [and] Margaret Rouse. - [New York Rinehart [1955] - 455 p. illus. LCCN: 55010133 /L Subjects--Topical Terms: Education , Elementary LC Class. No.: LB875 / .O83 1955 Dewey Class. No.: 372