Palmer, Alan, author
Penguin Books, 1981
Buku Referensi
Henry, John, chief-medical editor
Dorling Kindersley, 1995
Buku Referensi
Williams, Norma
Tiger Books International, 1990
Buku Referensi
Wolfe, Gerard R., author
McGraw-Hill, 1994
Buku Referensi
edited by Gerald W. Whitted
Pan American World Airways, 1971
Buku Referensi