McClure, William, author
Cambridge University Press, 2000
Buku Teks
Freund, John E., author
McGraw-Hill, c1966
Buku Teks
Buku Referensi
Ogden, C. K. (Charles Kay), 1889-1957, author
Evans Brothers, [1940]
Buku Referensi
Walters, Morgan L
N.Y.Holt Rinehart and Winston,inc, 1966
Buku Teks