Gasponi, Giancarlo, author
Euroedit-Trento, 1995
Buku Referensi
Breton, Guy
Coward-McCann , 1966
Buku Teks
Gibbon, Edward, author
Random House, 1994
Buku Referensi
Dautray, Robert
Springer-Verlag, 1990"
Buku Teks
Willardson, Robert K.
Reinhold Pub. Co., 1962
Buku Teks