Ļevina, Jeļena, et al. “Characteristics of Personal Value-Meaning Systems of Latvian Youths in 1998, 2005, 2010 and 2015: A Comparative Study”. SOCIETY. INTEGRATION. EDUCATION. Proceedings of the International Scientific Conference, vol. 3, May 2015, pp. 577-8, https://doi.org/10.17770/sie2015vol3.476.