Clark, Colin, The economics of subsistence agriculture, by Colin Clark and Margaret Haswell. - 4th ed. - London: New York: Macmillan, St. Martin's P., 1970. - xiv, 267 p.; illus.; 22 cm. Bibliography: p. 245-257. ISBN: 0333036883 Subjects--Topical Terms: Agriculture--Economic aspects. Dewey Class. No.: 338.1 CAL