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Buku Teks
Siagian, Sondang P., author
Bumi Aksara , 2008
Buku Teks
Crosbie, Liz
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Buku Teks
Hagve, D.C.
English Longvage Book Society and Longman Group , 1969
Buku Teks
Siagian, Sondang P., author
Bumi Aksara, 1998
Buku Teks