Emerson, Thomas I.
Vintage Books, 1970
Buku Teks
Corbett, Michael,
Longman, 1982.
Buku Teks
edited by Burke Marshall
National Public Radio, 1982
Buku Teks
Emerson
Little,Brown and Company, 1981
Buku Teks
Tresolini, Rocco J.
J.B. Lippincott, 1963
Buku Teks