Bussmann, Hadumod
Routledge, 1996
Buku Referensi
Longman, 1984
Buku Referensi
Palmer, E.H.
Routledge & Kegan Paul, 1956
Buku Referensi
Marsden, William
Oxford University Press, 1984
Buku Referensi
Boyle, John Andrew
Luzac & Company, 1949
Buku Referensi