edited by Dianne Watkins
Bailliere Tindall, 2003
Buku Teks
Dever, G. E. Alan, author
Aspen Systems Corp., 1980
Buku Teks
Gray, Stephen E.
MacMillan Press , 1978
Buku Teks
Smolensky, Jack
W B Saunders company, 1972
Buku Teks
Herman, Harold
International City Managers Association, 1968
Buku Teks