Ashlock, Robert B. Hatfield, Mary M. Hausher, Howard L. Stoeckinger, John H. text Columbus, Ohio Merrill Publishing Co. c1987 monographic viii, 472 p. : some col. ill. ; 24 cm. Dr.Robert B. Ashlock [and three others]. Includes glossary and index. Mathematics 510 G326 1987 0-675-04800-1