Colarik, Andrew M, author
IDEA Group, 2006
Buku Teks
George Allen and Unwin, 1963
Buku Teks
Benham, Frederic, author
Oxford University Press, 1962
Buku Teks
Fituni, L.A., author
Progress Publishers, 1963
Buku Teks
Kautsky, John H.
John Wiley & Sons, 1967
Buku Teks