Buck, Carl Darling, author
Chicago, Chicago University Press 1949
Buku Referensi
Gramedia Pustaka Utama, 2005
Buku Teks
Thomas, Joseph, author
Philadelphia : J.B. Lippincott, 1915
Buku Referensi
Hartmann, Reinhard R.K., author
Routledge, 1998
Buku Referensi
Himus, Godfrey W., author
Harmondsworth, Middlesex, 1954
Buku Referensi