de Vries, Dominic, author
Gabler Verlag, 2011
eBooks
Stim, Richard, author
West Thomson Learning, 2001
Buku Referensi
Siti Budi Mulyasari, author
2012
UI - Tesis (Open)
Edwards, Douglas, author
Polity Press, 2014
Buku Teks
Stanford Research Institue, 1960
Buku Teks