R., J., S. et al.(1989).1988 World food conference proceedings / editor, John W. Helmuth, Stanley R. Johnson (Ed.ke-1).:Iowa State University Press for the Center of Agricultural and Rural Development.
Gaya MLA
Johnson, Stanley, R.. et al."1988 World food conference proceedings / editor, John W. Helmuth, Stanley R. Johnson".Ed.ke-1:Iowa State University Press for the Center of Agricultural and Rural Development,1989.Textbook.