Guoqi, Xu
Oxford University Press, 2017
eBooks
Fleischman, Richard
L'Arcaedizioni, 1996
Buku Teks SO
Maple, Frank F.
Sage, 1989
Buku Teks SO
G20 Seoul Sumit 2010, 2010
Majalah, Jurnal, Buletin
edited by Lauren B. Resnick, John M. Levine, and Stephanie D. Teasley
American Psychological Association, 1991
Buku Teks SO