Parris, Melanie, author
McGraw-Hill, 2012
Buku Teks
edited by Sarah Gehlert; Teri Arthur Browne
John Wiley & Sons, 2012
Buku Teks
Hess, Hartmut, author
International Friedrich-Erbert-Stftung (FES), 2006
Buku Teks
Skidmore, Rex A. (Rex Austin), author
Prentice Hall International, 1991
Buku Teks
Ferguson, Elizabeth A., author
J.B. Lippincott, 1975
Buku Teks