Francis, Thomas George, author
ELBS, 1992
Buku Teks
Francis, Thomas George, author
Longman, 1971
Buku Teks
Kirchner, Harold B., author
McGraw-Hill, 1978
Buku Teks
Zunaedi, author
1996
UI - Skripsi (Membership)
Loyd, Richard, author
NY : Thomson Delmar Learning, 2004
Buku Teks