Grigg, David B. The agricultural systems of the world : an evolutionary approach / 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 0521098432 Source: B-9852 LCCN: 73082451 Subjects--Topical Terms: Agricultural geography.Agriculture--History. LC Class. No.: S439 / .G74 1974