Automatic data-processing systems : principles and procedures / by Robert H. Gregory and Richard L. Van Horn. Gregory, Robert Henry. Van Horn, Richard L., joint author. Business Data processing. HF5548.2 .G68 1963 651.26 GRA includes index. "Guide to the literature": p. 780-788. Belmont, Calif. : Wadsworth Pub. Co. ; 1963. 1963. 1963 Text xi, 816 p. : eng Wadsworth accounting and data processing series.