The Deal Magazine, October 14, 2011 by David Marcus
http://www.thedeal.com/magazine/ID/042051/features/trolls,-geeks-and-lots-of-lawyers.php
“One way to think about how many patents you need is to look at how many patents companies with similar revenues have,” Barr says. “I looked at reaching at least a filing rate per year that met what other companies were doing adjusted for revenue.”