Barry, Sir Gerald, editoral board
Doubleday, 1965
Buku Referensi
Koelb, Clayton
Cornell University Press , 1988
Buku Teks SO
edited by John Paynter, Tim Howell, Richard Orton and Peter Seymour
Routledge , 1992
Buku Referensi
edited by John Paynter, Tim Howell, Rchard Orton and Peter Seymour
Routledge, 1992
Buku Referensi
Pasaribu, Amir
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Buku Teks SO