?url_ver=Z39.88-2004&rft_id=10.1097%2FQAI.0b013e318239c947&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Yan%2C+H&rft.aulast=Yan&rft.aufirst=H&rft.issue=2&rft.volume=59&rft.date=1+February+2012&rft.issn=1525-4135&rft.atitle=Long-chain+peer+referral+of+men+who+have+sex+with+men%3A+A+novel+approach+to+establish+and+maintain+a+cohort+to+measure+HIV+incidence%2C+Nanjing%2C+China&rft.title=Journal+of+Acquired+Immune+Deficiency+Syndromes&rft.pages=177+-+184&rft.genre=article