@techreport{Kaplan2012,
author = {Kaplan, G. and Schulhofer-Wohl, S.},
title= {Understanding the long-run decline in interstate migration},
year = {2012},
doi = {10.3386/w18507},
publisher = {National Bureau of Economic Research },
address = {Cambridge},
number = {NBER Working Paper 18507},
}