Collins, 2002
Buku Referensi
Langenscheidt, 1993,
Buku Referensi
edited by Alton Bryant
Minnesota , Billy Graham Evangelistic Association
Buku Referensi
[publisher not identified], [date of publication not identified]
Buku Teks
Wallace, W. Stewart, author
Macmillan, 1945
Buku Referensi