Are Ureaplasma spp. a Cause of Nongonococcal Urethritis? A Systematic Review and Meta-Analysis Zhang, Nan ; Wang, Rong ; Li, Xue ; Liu, Xu ; Tang, Zhaobing ; Liu, Yunde Abstract Publication: PLoS ONE Pub Date: December 2014 DOI: 10.1371/journal.pone.0113771 Bibcode: 2014PLoSO...9k3771Z