Weaver, John E. 1884-1966. Plant ecology / by John E. Weaver and Frederic E. Clements. - 2d ed. - New Delhi : Tata McGraw-Hill, 1973 - xxii, 601 p. incl. front. (map) ill., diagrs. ; 24 cm. Bibliographies : p. 539-582 Subjects--Topical Terms: Botany--Ecology.