@article{Greenwood2015,
author = {Greenwood, M.J. and Ward, Z.},
title= {Immigration quotas, World War I, and emigrant flows from the United States in the early 20th century},
year = {2015},
doi = {10.1016/j.eeh.2014.05.001},
volume = {55},
pages = {76--96},
}