Schwartz, Melvin. Exploring a changing world / Melvin Schwartz, John R. O'Connor. - New York : Globe Book Co., c1984. - xiii, 626 p. : ill. (some col.) ; 27 cm. Includes index. ISBN: 0870656112 LCCN: 84113690 LC Class. No.: HF1027 .S3 1984 / .S3 1984 Dewey Class. No.: 909