[1] INST MEXICANO SEGURO SOCIAL, CTR MED LA RAZA, HOSP ESPECIALIDADES, DEPT RHEUMATOL, MEXICO 15, DF, MEXICO
[2] INST NACL NUTR, DEPT IMMUNOL & RHEUMATOL, MEXICO CITY 22, DF, MEXICO
[3] INST MEXICANO SEGURO SOCIAL, CTR MED NACL, DEPT RHEUMATOL, MEXICO 7, DF, MEXICO