@article{Hanushek2015,
author = {Hanushek, E.A. and Schwerdt, G. and Wiederhold, S. and Wößmann, L.},
title= {Returns to skills around the world: Evidence from PIAAC},
year = {2015},
doi = {10.1016/j.euroecorev.2014.10.006},
volume = {73},
pages = {103--130},
}