Allen, Carleton Kemp, Sir
Oxford University Press, 1943
Buku Teks
Allen, Carleton Kemp, Sir
Stevens & Sons Limited, 1958
Buku Teks
Schulz, Ernest B
[publisher not identified], 1956
Buku Teks
Arblaster, Anthony, author
Open University Press, 1987
Buku Teks
Allen, Carleton Kemp, Sir
Stevens & Sons Limited, 1953
Buku Teks