Yorston, Robert Keith, Sir.
Law Book Company, 1966
Buku Teks
Hollins, Carole
Blackwell Munksgaard, 2006
Buku Teks
La Londe, William S., editor
New York: McGraw-Hill, 1991
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Cambridge University
Cambridge university press, 2000
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Hopkins, Diana
Cambridge University Press, 2011
Buku Teks