Dunteman, George Henry
Sage Publications, 1984
Buku Teks
Raykov, Tenko, author
Routledge, Taylor & Francis Group, 2008
Buku Teks
Kachigan, Sam Kash, author
Radius Press, 1991
Buku Teks
Karson, Marvin J., author
Iowa State University Press, 1982
Buku Teks
Cooley, William W., author
John Wiley & Sons, 1971
Buku Teks