Hainmueller, J. ., Lawrence, D. ., Gest, J. ., Hotard, M. ., Koslowski, R. ., & Laitin, D. . (2018). A randomized controlled design reveals barriers to citizenship for low-income immigrants. Proceedings of the National Academy of Sciences of the United States of America. https://doi.org/10.1073/pnas.1714254115 (Original work published 2018)