[1] SEATTLE KING CTY DEPT PUBL HLTH, SEATTLE, WA USA
[2] ST LOUIS DEPT HLTH, ST LOUIS, MO USA
[3] LOUISIANA STATE UNIV, NEW ORLEANS, LA USA
[4] DENVER DIS CONTROL SERV, DENVER, CO USA
[5] UNIV COLORADO, DENVER, CO 80202 USA
[6] CALIF MED RES GRP, FRESNO, CA USA
[7] FRESNO CTY HLTH DEPT, FRESNO, CA USA
[8] EPISCOPAL HOSP, PHILADELPHIA, PA USA
[9] MED COLL PENN, PHILADELPHIA, PA 19129 USA
[10] INDIANA UNIV, INDIANAPOLIS, IN 46204 USA
[11] BOSTON CITY HOSP, BOSTON, MA 02118 USA
[12] SAN FRANCISCO GEN HOSP, SAN FRANCISCO, CA 94110 USA
[13] NATL IND, MONTGOMERY, AL USA