Artikel Jurnal
by Yoichi Okazaki [and others]
Foreign Press Center, 1990
Buku Teks
Hillier, Susan, author
Wadsworth and Cengage Learning, 2011
Buku Teks
edited by Clark Tibbitts and Wilma Donahue
Prentice-Hall, 1960
Buku Teks
edited by John Field, Ronald J. Burke and Cary L. Cooper.
SAGE, 2013
Buku Referensi