Japan Times, 1982
Buku Teks
Bloomfiel, L. M.
The Carswell Company, Limited, 1957
Buku Teks
edited by Bernhard M. Riegl and Sam J. Purkis
Springer, 2012
eBooks
Nainggolan, Poltak Partogi, 1963-, author
Yayasan Pustaka Obor Indonesia, 2020
Buku Teks
Westview Press, 1988
Buku Teks