Smith, Thomas C.
University of California Press, 1988
Buku Teks SO
University of California Press, 1976
Buku Teks
Indra Wahyuningsih
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 1987
UI - Skripsi Membership
Dyson, John
Kestrel Books, 1976
Buku Teks
Harrison, George Russell
Franklin Watts, 1965
Buku Teks SO