Study Search Results Your query returned 4 results. Series results are grouped under the most relevant study. You can ungroup series 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. Puerto Rico's Padrones, 1779-1802 (ICPSR 30262) Scarano, Francisco A.; Curtis, Katherine J. 3. Union Army Recruits in Black Regiments in the United States, 1862-1865 (ICPSR 9426) Metzer, Jacob; Margo, Robert A. 4. Union Army Recruits in Black Regiments in the United States, 1862-1865: [Instructional Materials] (ICPSR 3466) Oberly, James W.