edited by Gerald W. Whitted
Pan American World Airways, 1963
Buku Referensi
Carvan, J.C.
LBC Information Service, 1997
Buku Teks
Sudargo Gautama, author
Alumni, 1993
Buku Teks
Kennedy-Grant, Tomas
Butterworth, 1999
Buku Teks
Oxford Univesity Press, 2008
Buku Referensi