Fuller, Lon L.
The morality of law
Yale University Press, 1964
 Buku Teks SO
Fuller, Lon L.
The morality of law
Yale University Press, 1974
 Buku Teks SO
Martin, Virginia
Law and custom in the steppe
Curzon, 2001
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Meek, C.K.
Land law and custom in the colonies
Oxford University Press, 1949
 Buku Teks SO
Wolfke, Karol
Custom in present international law
Martinus Nijhoff, 1993
 Buku Teks SO