Romeo, Luigi, author
Amsterdam John Benjamins 1979
Buku Referensi
Depok : Departemen Filsafat FIB-UI, 2005,
Majalah, Jurnal, Buletin
Darwin, Charles, author
New York The Modern Library [date of publication not identified],
Buku Teks
Seeley, John Robert, author
JM Dent & Sons, 1932
Buku Teks
Hasselaar, J.M.
s-Gravenhage Bookencentrum 1953
Buku Teks