NEKRAŠAS, Evaldas. Frequency Interpretation of Probability. Problemos, [S. l.], v. 7, p. 32–39, 1971. DOI: 10.15388/Problemos.1971.7.5809. Disponível em: https://www.journals.vu.lt/problemos/article/view/5809. Acesso em: 5 dec. 2025.