1. D.N. Aspin and J.D. Chapman, ‘Lifelong learning: concepts and conceptions’. International Journal of Lifelong Education (2000) vol 21, 535–565.
2. R. Boerini and H. Strauss, ‘What is the Private Return to Tertiary Education? New Evidence from 21 OECD Countries’. OECD Journal: Economic Studies (2010) vol 2010, 25.
3. A. de la Fuente and F.J. Jimeno, ‘The Private and Fiscal Returns to Schooling and the Effect of Public Policies on Private Incentives to Invest in Education: A General Framework and Some Results for the EU’. Banco de España Working Papers (2009) vol 0509.
4. M. Dziechciarz-Duda and A. Krol, ‘An Application of Mincer Model in Analysis of Higher Education Influence on the Wages’. Level, Ekonometria (2012) vol 3, no 37, 56–69.
5. J.Z. Dziechciarz, ‘Measurement of Rate of Return in Education. Research Directions (November 20, 2015)’ in Jolán Velencei Ph.D. (ed.), Proceedings of FIKUSZ 2015 (2015), Óbuda University, Budapest, 39–56.