Martin, Anne
Routledger Kegan Paul , 1958
Buku Teks
Hubbard, Leonard E.
MacMillan, 1939
Buku Teks
Wilcox, Walter W.
Prentice-Hall, 1951
Buku Teks
Ross, Robert C.
McGraw-Hill, 1951
Buku Teks
the Australian Agricultural Economic Society, 1989
Majalah, Jurnal, Buletin