Amstrong, Michael
Crest Publishing House, 1999
Buku Referensi
Armstrong, Michael
Gramedia, 2003
Buku Teks
Armstrong, Michael
Gramedia, 2003
Buku Teks
Armstrong, Michael
[Publisher not identified], [Date of publication not identified]
Buku Teks
Hunsaker, Phillip L.
A Touchstone Book, 1986
Buku Teks