Sykes, Egerton
London, J.M. Dent and Sons
Buku Referensi
Reinbek bei Hamburg Rowohlt Taschenbuch Verlag GmbH 1988
Buku Teks
Jones, Daniel
Cambridge University Press, 1992
Buku Referensi
Kenyon, John Samuel
Merriam-Webster ; G. & C. Merriam Co., 1953
Buku Referensi
Jones, Daniel
Everymans`s Reference Library, 1956
Buku Teks SO