Artikel Jurnal
Kerman, Joseph
Worth Publishers, 1996
Buku Teks
edited by Michael J. Novacek and Quentin D. Wheeler
Columbia Univerdity Press, 1992
Buku Teks
Swanson, Timothy M., author
Macmillan, 1994
Buku Teks
Courtillot, Vincent, author
Cambridge University Press, 1999
Buku Teks