Steel, Danielle
Gramedia Pustaka Utama, 2001
Buku Teks SO
Tindall, William York
Books for Libraries Press, 1947
Buku Teks SO
Matondang, Saiful Anwar
1997
UI - Tesis Membership
Brown, Christy
Secker & Warburg, 1976
Buku Teks SO
Long, David
Scribner, 1997
Buku Teks SO