Artikel Jurnal
Tuuk, H.N. van der, author
Martinus Nijhoff, 1971
Buku Teks
Marbun, M.A., author
Balai Pustaka, 1987
Buku Referensi
Warneck, Joh., author
Martinus Nijhoff, 1977
Buku Referensi
Simanjuntak, Sophar, author
Yayasan Pustaka Obor Indonesia , 2015
Buku Teks