Reducing bias in parameter estimates from stepwise regression in proportional hazards regression with right-censored data.
Lifetime Data Analysis
http://www.ncbi.nlm.nih.gov/pubmed/?term=Reducing%20bias%20in%20parameter%20estimates%20from%20stepwise%20regression%20in%20proportional%20hazards%20regression%20with%20right-censored%20data.