Stephany Efflina, author
Universitas Indonesia, 2009
UI - Skripsi Open
Nandita Erisca
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 2008
UI - Skripsi Open
Skinner, Stephen, author
Parragon, 1997
Buku Referensi
Dy, Victor L., author
Elex Media Komputindo, 1997
Buku Teks
Lip, Evelyn, author
Times Books International , 1995
Buku Teks