Parents' Magazine's Cultural Institute, 1965
Buku Referensi
Turner, Ralph
McGraw-Hill, 1941
Buku Teks
Gilman, Sander L.
Polity Press, 2008
Buku Teks
Mohammed Ali
Punjab Eductional Press, 1964
Buku Teks
Sansom, George Bailey, Sir, 1883-1965
Cresset Press, 1946
Buku Teks