Woll, Peter
Longman , 2001
Buku Teks
Woll, Peter
Little, Brown, 1965
Buku Teks
Presser, Stephen B.
St.Paul, Minn., 1980
Buku Teks
by William B. Lockhart ... [and others]
West Publishing Company, 1975
Buku Teks
Hall, Kermit L.
Oxford University Press, 1991
Buku Teks