Martin, John Henry, 1915- Free to learn : unlocking and ungrading American education / by John Henry Martin & Charles H. Harrison - Englewood Cliffs, N.J. : Prentice-Hall, 1972 - vi, 185 p. ; 21 cm. - A Spectrum book . Includes bibliographical references ISBN: 0133310663 USD 5.95 Subjects--Topical Terms: Education--United StatesEducation--History Dewey Class. No.: 370.973