Longrigg, Stephen Hemsley, author
Oxford University Press , 1956
Buku Teks
Marr, Phebe
Colorado Westvies Press, 1985
Buku Teks
Longrigg, Stephen Hemsley, author
Frederick A. Praeger, 1958
Buku Teks
Director-General of guidance and Broadcasting, 1956
Buku Teks
Donaldson, Dwight M., author
Luzac & Company, 1933
Buku Teks