1. Department of Biostatistics; Mailman School of Public Health; Columbia University; New York; New York
2. School of Mathematical Sciences; Fudan University; Shanghai; P.R. China
3. National Cancer Institute; Bethesda; Maryland
4. Center for Statistical Genetics; The Pennsylvania State University; Hershey; Pennsylvania
5. Columbia Center for Children's Environmental Health; Mailman School of Public Health; Columbia University; New York; New York