Gaya APA

1.j., . (1981). Will There Be Enough food ; The 1981 Yearbook of Agriculture . Washingtoon, D.C.: U.S. Government Printing Office.

Gaya MLA

1.j., . "Will There Be Enough food ; The 1981 Yearbook of Agriculture". Washingtoon, D.C.: U.S. Government Printing Office, 1981. Text.