Ennis, Robert Hugh, 1927- Logic in teaching / by Robert H. Ennis - Englewood Cliffs, N.J. : Prentice-Hall, 1969 - xiv, 520 p. : illus. 24 cm. Includes bibliographical references. ISBN: 135400961t LCCN: 69-017479 Subjects--Topical Terms: Logic in teaching