Allen, C.F.H. Six membered hetrocyclic nitrogen compounds with four condensed rings C.F.H. Allen, collaborated with D.M. Burness and others. - New York Interscience publishers 1951 - xiii, 345p. Contents: v.2 The chemistry of hetrocyclic compounds. Subjects--Topical Terms: Chemistry, Organic Organic compounds. Dewey Class. No.: 547.7 / A39S