edited by George Watson
Cambridge University Press, 1971
Buku Referensi
edited by I.R. Willison
Cambridge University Press, 1972
Buku Referensi
edited by Douglas Daymond and Leslie Monkman
Gage Educational Publishing Limited, 1978
Buku Teks
Otis, William Bradley, author
Barnes & Noble, [c1937]
Buku Teks
edited, B.J. Whiting .. .[et al.]
Harcourt, Brace & World, 1942
Buku Teks