penyunting, Poltak Partogi Nainggolan
Balai Pustaka, 2016
Buku Teks
Minstry Foreign Affairs, [date of publication not identified]
Buku Teks
by J. Swiericzuk ... [and others]
Pitman, 1980
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Fernandez, Alejandro M.
NSDB-UP Integrated Research Program, 1977
Buku Teks
Fairbank, John K. (John King)
Vintage Book, 1976
Buku Teks