POVILONIS, Salezijus. Some Aspects of Secular Trend. Problemos, [S. l.], v. 1, p. 97–104, 1968. DOI: 10.15388/Problemos.1968.1.5710. Disponível em: https://www.journals.vu.lt/problemos/article/view/5710.. Acesso em: 28 apr. 2024.