1. OECD Digital Economy Outlook 2015
2. Cedefop Skills Panorama 2016a http://skillspanorama.cedefop.europa.eu/en/analytical_highligths/information-and-communication-technology-professionals-skills-opportunities
3. U.S. Bureau of Labor Statistics 2015 http://www.bls.gov/ooh/
4. Cedefop 2016b http://www.cedefop.europa.eu/en/publications-and-resources/publications/9115
5. Human capital estimation in higher education;Lovaglio;Adv. Data Anal. Classif.,2016