Towards a general non-parametric model of corporate performance
Omega, Volume 22, Issue 3, May 1994, Pages 237-249
A Fernandez-Castro, P Smith
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VC4-48M34BS-G&_user=10&_coverDate=05/31/1994&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=4015c36f21005c7839b8a316279026e1