Friedrich, Klaus
McGraw-Hill Kogakusha, 1974
Buku Teks
by George Zis ... [et al.]
Longman, 1988
Buku Teks
Salvatore, Dominick, author
Prentice-Hall, 1995
Buku Teks
Salvatore, Dominick, author
John Wiley & Sons, 2007
Buku Teks
Ellsworth, P.T., author
Macmillan, 1975
Buku Teks