Physical description for original version: vi, 41 p. : 28 cm
書誌注記
Includes bibliographical references
原資料等に関する注記
原資料の出版事項: [Washington, DC] (1301 New York Ave., NW, Washington 20005-4788) : U.S. Dept. of Agriculture, Economic Research Service, Agriculture and Rural Economy Division, [1989]