1. Division of Biostatistics, School of Public Health, The Univerity of Minnesota, Minneapolis, USA
2. Division IV, Office of Biostatistics/OTS/CDER/FDA, Spring, USA
3. Division of Biostatistics, School of Public Health, The University of Texas Health Science Center, Houston, USA
4. Departemt of Mathematics and Statistics, University of Maryland, Baltimore County, Baltimore, USA
5. Department of Biostatistics and Genetics, The Univerity of North Carolina, Chapel Hill, USA.