Development of a large urban longitudinal HIV clinical cohort using a web-based platform to merge electronically and manually abstracted data from disparate medical record systems: technical challenges and innovative solutions. - Greenberg, Alan E.; Hays, Harlen; Castel, Amanda D.; Subramanian, Thilakavathy; Powers Happ, Lindsey; Jaurretche, Maria; Binkley, Jeff; Kalmin, Mariah M.; Wood, Kathy; Hart, Rachel; Happ, Lindsey Powers; DC Cohort Executive Committee (Journal of the American Medical Informatics Association, 2016)