Damiana Iki, author
Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 1988
UI - Skripsi (Membership)
Joshi, A.W., author
Wiley Eastern, 1982
Buku Teks
Baumslag, Benjamin, author
McGraw-Hill, 1968
Buku Teks
Milewski, Emil G., author
Research and Education Association, 1989
Buku Teks
Academic Press , 1977
Buku Teks