edited by Christopher G. Reddick, Stephen K. Aikins
Springer, 2012
eBooks
Paris : The United Nations Educational
Majalah, Jurnal, Buletin
Slemon, Gordon R.
Addison-Wesley, 1980
Buku Teks SO
Mychael, Arthur
McGraw-Hill, 1977
Buku Teks
edited by H.O. Leilich and M. Missikoff
Springer-Verlag, 1983
Buku Teks