Metcalf, John, author
Oberon Press, 1978
Buku Teks
Astley, Thea, author
Angus and Robertson, 1958
Buku Teks
Hilliard, Noel, author
Heinemann, 1971
Buku Teks
Sindi Fatimah Dewantari Nugraha, author
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2017
UI - Skripsi Membership
Baldwin, Ralph B., author
McGraw-Hill, c1965
Buku Teks