Chicago: Encyclopedia Britanica, 2002,
Buku Referensi
Loehrer, Patrick J.
Elsevier, 2005
Buku Referensi
Chicago : encyclopaedia Britanica Inc, 2000,
Buku Referensi
Chicago : encyclopaedia Britanica Inc, 1999,
Buku Referensi
editor-in-chief, Marjorie A. Bowman ; editor, Barbara S. Apgar ... [and others]
Elsevier Mosby, 2005
Buku Referensi