Supervision : democratic leadership in the improvement of learning / A.S. Barr, William H. Burton, Leo J. Brueckner Barr,A. S. Burton, William H. jt auth. Brueckner, Leo J. jt auth. Education 371.1 BAS Includes bibliographical references and index. New York : Appleton-Century Crofts, 1938. 1938. 1938 Text viii, 879 p : eng