edited by Leo Goedegebuure ... [and others]
Pergamon Press, 1994
Buku Teks
editors, Hans G. Schuetze, German Alvarez Mendiola
Sense, 2012
eBooks
Center for International Higher Education Boston Collage,
Majalah, Jurnal, Buletin
Bernhard, Andrea, author
VS Research, 2012
eBooks
edited by William H. Allaway
Westview Press, 1985
Buku Teks