%0 Journal Article %T Primary and secondary syphilis. Country of origin study, 1968. British Cooperative Clinical Group. %D 1970 %R 10.1136/sti.46.1.69 %J The British Journal of Venereal Diseases %P 69-75 %V 46 %N 1 %U https://sti.bmj.com/content/sextrans/46/1/69.full.pdf