Butts, R. Freeman
Beacon Press, 1950
Buku Teks
oleh Zainal Abidin Ahmad
1766, 1968
Buku Teks
Weber, Max, 1864-1920, author
Duncker & Humblot, 1956
Buku Teks
M. Nasroen, author
Pasaman, 1957
Buku Teks
Laski, Harold J., author
George Allen and Unwin, 1935
Buku Teks