1. Office of Retirement Policy, U.S. Social Security Administration, 500 E. Street, SW, 9th floor, Washington, DC 20254, USA
2. Department of Sociology, University of Kansas, 1415 Jayhawk Boulevard, Room 716, Lawrence, KS 66045, USA
3. Department of Sociology, Texas A&M University, 311 Academic Building, 4351 TAMU, College Station, TX 77843, USA