Mueller, Rudolf
Fritz Knapp Verlag, 1972
Buku Teks
Irene Chow [and others]
Prentice-Hall, 1997
Buku Teks
Business International Asia/Pacific , 1992
Buku Teks
edited by Malcolm Warner
Business Press, 2000
Buku Referensi
Nichilson, Mary Jo
Prentice-Hall, 1997
Buku Teks