Colombus, C. John
Longmans, 1959
Buku Teks
Booth, Ken, author
George Allen and Unwin, 1985
Buku Teks
Colombos, C. John, author
Longman, 1959
Buku Teks
Sohn, Louis B., author
Thomson Reuters, 2010
Buku Teks
Tanaka, Yoshifumi, author
Cambridge University Press, 2012
Buku Teks