That is also the view of Joshua Rosner, a managing director at Graham & Fisher & Co., and Joseph Mason, associate professor of finance at Drexel University's LeBow College of Business. The two published a paper last week, "How Resilient Are Mortgage- Backed Securities to Collateralized Debt Obligation Market Disruptions?" analyzing CDOs. The Hudson Institute, a nonpartisan policy research organization in Washington, financed their research.