Worrall, Jean. Introduction to valence theory, by Jean Worrall and I. J. Worrall. - New York, American Elsevier Pub. Co., 1969. ISBN: 0444197079 3.95 LCCN: 74099464 //r86 Subjects--Topical Terms: Valence (Theoretical chemistry) LC Class. No.: QD469 / .W67 1969 Dewey Class. No.: 541/.224