Morales-Macedo, Fernando
Alphen Aan den Rijn, 1979
Buku Teks
Egbert, Lawrence Deems
Oceana, 1979
Buku Referensi
general editors, Clive Parry, John P. Grant, Anthony Parry, Arthur D. Watts
Oceana Publications, 1988
Buku Referensi
Ross, Martin J., author
Prentice-Hall, 1977
Buku Teks
London: Tiger Books International, 1994,
Buku Referensi