J. Ļevina, K. Mārtinsone, S. Mihailova, and I. Gintere, “Characteristics of Personal Value-Meaning Systems of Latvian Youths in 1998, 2005, 2010 and 2015: A Comparative Study”, SIE, vol. 3, pp. 577–587, May 2015, doi: 10.17770/sie2015vol3.476.