Leech, Margaret, 1893-1974, author
Harper, 1959
Buku Teks
Davies, W.H.
J. Cape,, 1927
Buku Teks
Bent, Ralph D.
McGraw-Hill, 1981
Buku Teks
Hebert, Jacques, author
Optimum Publishing International, 1986
Buku Teks
Schlesinger, Arthur M., author
A Marner Book, 2003
Buku Teks