Beckett, Grace
Russell & Russell, 1972
Buku Teks
Pfitzer, Gregory M., author
Northeastern University Press, 1991
Buku Teks
Distributed Art Publishers, Birmingham
Buku Teks
Roberts, S.C., author
Longmans, Green, 1965
Buku Teks
Beckett, H.E.
Van Nostrand Reinhold, 1974
Buku Teks