1. University of Northern Iowa, 356 Baker Hall, Cedar Falls, IA 50614-0513, USA
2. Center for Health Statistics, New Jersey Dept. of Health & Senior Services, 171 Jersey St., Building 5, 2nd Flr., PO Box 360, Trenton, NJ 08625 0360, USA
3. 222 Sloan College, University of South Carolina, Columbia, SC 29208, USA