1. James Bell Associates, Arlington, Virginia, USA
2. National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, U.S. Dept. of Health and Human Services, Atlanta, Georgia, USA
3. Children’s Bureau, Administration for Children and Families, U.S. Dept. of Health and Human Services, Washington, District of Columbia, USA
4. Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee