Study Search Results Your query returned 2 results. Results per page: 25 50 100 Sort by: Title A-Z Released/Updated Time Period Most Cited in ICPSR Bib. (?) Study Title/Investigator 1. Philadelphia Social History Project: Pennsylvania Abolition Society and Society of Friends Manuscript Census Schedules, 1838, 1847, 1856 (ICPSR 3805) Hershberg, Theodore 2. Union Army Recruits in Black Regiments in the United States, 1862-1865 (ICPSR 9426) Metzer, Jacob; Margo, Robert A.