Gawron, Valerie J., author
CRC Press, Taylor & Francis Group, 2008
Buku Referensi
Bailey, Robert W., author
Prentice-Hall, 1982
Buku Referensi
Baumgartner, Ted A., author
McGraw Hil , 2013
Buku Teks
edited by John E. Morrison
Wiley, 1991
Buku Teks
Baumgartner, Ted A., author
McGraw-HIll, 2002
Buku Teks