Grigg, David B. The agricultural systems of the world : an evolutionary approach / eng D. B. Grigg. - London ; New York : Cambridge University Press, 1974. - ix, 358 p. : maps ; 24 cm. - Cambridge geographical studies ; 5 . Includes index. Bibliography: p. 308-343. ISBN: 0521202698 : LCCN: Nat. Bib. No.: GB*** Subjects--Topical Terms: Agricultural geography.Agriculture--History. Dewey Class. No.: 631 / GRI