Research methods and teachers' problems : a manual for systematic studies of classroom procedure / by Douglas Waples and Ralph W. Tyler Waples, Douglas, 1893-1978. Tyler, Ralph W. (Ralph Winfred), 1902-1994 joint author. Teaching. Research. LB1025 .W33 370.78 WAR Includes bibliographical references and index. New York : Macmillan, 1930. 1930. 1930 Text xxiii, 653 p. : eng Half title: The modern teachers' series, ed. by W. C. Bagley