Burns, Edward McNall, 1897-1972, author
WW Norton, 1974
Buku Teks
Brinton, Crane, 1898-1968, author
Prentice-Hall, 1955
Buku Teks
Cambridge University Press, 2015
Buku Teks
Smith, Preserved, author
Cambridge University Press, 2014
eBooks
Hewlett, Richard G., author
Pennsylvania State University Press, 1962
Buku Referensi