Paul J. Krause John Fox Philip N. Judson Mukesh Patel Qualitative risk assessment fulfils a need. 138-156 http://link.springer.de/link/service/series/0558/bibs/1455/14550138.htm 1998 conf/drums/1998 Applications of Uncertainty Formalisms db/conf/drums/drums1998.html#KrauseFJP98