Richards, Jack C., author
Cambridge University Press, 2005
Buku Teks
Donald Freeman and Jack C. Richardsand , author
Cambridge Cambridge University Press 1996
Buku Teks
Anne Mc Kee
Springer, 2012
eBooks
Artikel Jurnal
edited by Donald J. Stedman, James L. Paul
Jossey-Bass Publishers, 1981
Buku Teks