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Buku Teks
Coleman, Frank M
University Toronto Press, 1977
Buku Teks SO
Latumahina, Freddy
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 2004
UI - Skripsi Membership
Robert Maynard Hutchins, editor in chief
Encyclopaedia Britannica, Inc., 1952
Buku Referensi
Carritt, E.F.
Clarendon Press, 1935
Buku Teks SO