Hartley, Ruth E. b.1909 Understanding children's play / by Ruth E. Hartley, Lawrence K. Frank [and] Robert M. Goldenson - New York : Columbia University Press, 1952 - 372 p. : ill. ; 22 cm. Includes bibliographical references and index Subjects--Topical Terms: Play--Psychological aspectsChild psychology Dewey Class. No.: 136.7479