Winfield, Percy Henry
Univercity Press, 1921
Buku Teks
Skegg, P. D. G.
Oxford Clarendon Press , 1984
Buku Teks
Kiralfy, A.K.R.
Sewwt & Maxwell Limited, 1960
Buku Teks
Amery, L.S.
Oxford University Press, 1953
Buku Teks
Collier, John Greenwood
Cambridge University Pers, 1994
Buku Teks