Serrano, Lorenzo, and Ángel Soler. “Human Capital in Spain and Its Distribution by Provinces (1964-2013)”. REGION 2, no. 1 (April 17, 2015): R3-R4. Accessed February 28, 2020. https://openjournals.wu-wien.ac.at/ojs/index.php/region/article/view/77.