Werner, Heinz. Comparative psychology of mental development / Heinz Werner. - Rev. ed. - New York : International Universities Press, 1948 , repr. 1957 . - xii, 564 p. : illus. ; 22 cm. Includes bibliographical references (p. 507-555) and index. Subjects--Topical Terms: Psychology, Comparative-------- Dewey Class. No.: 156 WER