Webb, John W. Programmable logic controllers : principles and applications / John W. Webb, Ronald A. Reis - 4th ed. - New Jersey : Prentice Hall, 1999 - xv, 443 p. : ill. ; 23 cm. Includes bibliographical references and index. ISBN: 0136794084 LCCN: 98-13424 Subjects--Topical Terms: Programmable controllers