Jackson, J. Hampden
Hougton Mifflin Company, 1956
Buku Teks
Wachters, H.J.J.
AD.M.C. Stok, [date of publication not identified]
Buku Teks
Salem Press , 1992
Buku Referensi
Salem Press , 1992
Buku Referensi
Grenville, J.A.S., author
Routledge, 2005
Buku Teks