KALVĀNS, Ēriks. Options of Using Oxford Happiness Survey of Latgale Inhabitants Happiness Structural Studies. SOCIETY. INTEGRATION. EDUCATION. Proceedings of the International Scientific Conference, Rezekne, Latvia, v. 3, p. 369–378, 2015. DOI: 10.17770/sie2015vol3.368. Disponível em: https://archive-journals.rtu.lv/sie/article/view/1172.. Acesso em: 11 mar. 2026.