Hubbard, L. Ron, 1911-1986, author
Bridge Publications, Inc., 2012
Buku Referensi
Hayes, William, author
John Wiley & Sons, 1978
Buku Teks
Mokichi Okada
Society of Johrey , 1984
Buku Teks
Auden, W.H., author
Oxford University Press, 1973
Buku Teks
The Clarendon Press, 1933
Buku Referensi