Reid, Ian, 1943-
Routledge, 1994
Buku Teks SO
Ariando Alfariz
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 2017
UI - Skripsi Membership
Boynton, Robert W.
Boynton/Cook, 1992
Buku Teks SO
Bendixen, Alfred
Wiley-Blackwell, 2010
Buku Teks SO
Shaw, Valerie
Longman, Green, 1994
Buku Teks SO