Mansbach, Richard W., author
Houghton Miffiln, 2000
Buku Teks
edited by Arthur S. Banks, Alan J. Day, Thomas C. Muller
CSA Publications, 1997
Buku Referensi
Friedmann, Wolfgang, 1907-1972, author
Macmillan, 1951
Buku Teks
Pearson-Prentice Hall, 2004
Buku Teks
D`anieri, Paul J., 1965-, author
Cengage Learning, 2017
Buku Teks