005720000a22001570004500003000900000005001700009110010200026245007800128264006000206490004400266300001000310041000800320650003200328650003400360650002000394PH-MaWHO20241108112204.0 aSymposium on Epidemiologic Studies and Clinical Trials in Chronic Diseases 1972 : Washington,D.C. aEpidemilogic studies and clinical trials in chronic disease : procedings. aWashington : bPan American Health Organization,c1973. a(PAHO scientific publication, no. 257). a106p. aeng aChronic diseasexCongresses aChronic diseasexEpidemiology aClinical trials