BBC Earth (Firm)
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Buku Referensi
Adamson, Hilary
The Asian Study Group , 1981
Buku Teks
British Broadcasting Corporation , 1979
Buku Teks
Sparrow, Giles, 1970-, author
Quercus, 2014
Buku Referensi
Bouman, K. Herman, author
E.J. Brill, 1949
Buku Teks