McClelland, David Clarence, author
Vakils, Feffer and Simon Private, 1961
Buku Teks
Luard, Evan, author
Macmillan, 1990
Buku Teks
Macandie, G. L.
Alfred Henry Pettifer, 1949
Buku Teks
Artikel Jurnal
Tomasson, Richard F., author
Random Home, 1970
Buku Teks