[1] UNIV WASHINGTON, DEPT MED, BACK PAIN OUTCOME ASSESSMENT TEAM, JD-23, SEATTLE, WA 98195 USA
[2] VET AFFAIRS MED CTR, HLTH SERV RES & DEV FIELD PROGRAM, SEATTLE, WA USA
[3] UNIV WASHINGTON, DEPT HLTH SERV, SEATTLE, WA 98195 USA
[4] TUFTS UNIV, SCH MED, DEPT REHABIL MED, BOSTON, MA 02111 USA