Moore, W. G., author
Penguin Books, 1974
Buku Referensi
Moore, W. G.
Penguin, 1974
Buku Referensi
Mather, P.M., author
John Wiley & Sons, 1976
Buku Teks
Van Riper, Joseph E., author
McGraw-Hill, 1971
Buku Teks
Trewartha, Glenn T., author
McGraw-Hill, 1967
Buku Teks