Varma, S.P., author
Rajawali, 2010
Buku Teks
Varma, S.P., author
RajaGrafindo Persada, 1999, 2007
Buku Teks
Ebenstein, William, author
Holt, Rinehart and Winston, 1962
Buku Teks
Hayes, Carlton J. H., author
Macmillan, 1932
Buku Teks
Cambridge University Press, 2010
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