Barrow, Colin, author
John Wiley & Sons, 2001
Buku Teks
edited by Gerald W. Whitted
Pan American World Airways, 1971
Buku Referensi
edited by Gerald W. Whitted
Pan American World Airways, 1963
Buku Referensi
Nicholson, Max, author
Penguin Books, 1970
Buku Teks
Collins, V.D., author
J.B. Lippincott, 1935
Buku Teks