Wilgus, A. Curtis, author
Barner & Noble, 1963
Buku Teks
Weintraub, Max, author
Regents, 1960
Buku Teks
Hallam, Henri
J.M. Dent & Sons LTD, 1936
Buku Teks
Dudden, Arthur Power, 1921-, author
University of Pennsylvania Press, 1963
Buku Teks
Holman, C. Hugh, author
Macmillan, 1986
Buku Referensi