"study number","owner","title","investigators","doi","time period"
"00020","ICPSR","Demographic Characteristics of the Population of the United States, 1930-1950: County-Level","Gardner, John; Cohen, William","http://dx.doi.org/10.3886/ICPSR00020.v1","1950"
"07753","ICPSR","Population Redistribution and Economic Growth in the United States:  Population Data, 1870-1960","Kuznets, Simon; Thomas, Dorothy Swaine","http://dx.doi.org/10.3886/ICPSR07753.v2","1960"