1. Selection bias in HMOs and PPOs: a review of the evidence.;Hellinger;Inquiry,1995
2. Selection bias in HMOs: a review of the evidence.;Hellinger;Med Care Res Rev,2000
3. Selection experiences in Medicare HMOs: pre-enrollment expenditures.;Call;Health Care Financ Rev,1999
4. Understanding biased selection in Medicare HMOs.;Mello;Health Serv Res,2003
5. Comparing mortality and time until death for Medicare HMO and FFS beneficiaries.;Maciejewski;Health Serv Res,2001