Affiliation: | 1. Department of Mathematical Sciences, University of Texas at Dallas, Richardson, Texas 75080, U.S.A.;2. Department of Statistics, University of Michigan, Ann Arbor, Michigan 48109, U.S.A.;3. Department of Statistics, University of Connecticut, Storrs, Connecticut 06269, U.S.A.;4. Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California 94158, U.S.A. |