Kers, Martin, 1944-
Bv Laren, 1984
Buku Referensi
Carroll, Burt Haring, 1896-
John Wiley & Sons, 1980
Buku Teks SO
Luciana, James
Rockport, 1999
Buku Teks SO
Imada Fatma
Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2006
UI - Tesis Membership
Bureau of Immigration Research, 1990
Buku Teks SO