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Buku Referensi
Harrold, Ann
Library Association, 1986
Buku Referensi
Davies, Celia, 1945-
Routledge, 2000
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Park, Patricia
Kluwer Law International, 2012
Buku Teks
Allen, R.G.D.
Macmillan, 1980
Buku Teks