Breeden, Stanley, author
Collins, 1973
Buku Teks
Turner, Ian, author
Hale & Iremonger, 1979
Buku Teks
Nadel, George, author
Cheshire, 1957
Buku Teks
Crawford, R. M.
Hutchinson's University Library, 1955
Buku Teks
Crawford, R.M., author
Hutchinson University Library, 1952.
Buku Teks