BURAČAS, Antanas. The Criteria and Principles of Investigation of Economic Activity (On Different Levels of Theoretical Interpretation). Problemos, [S. l.], v. 20, p. 34–38, 1977. DOI: 10.15388/Problemos.1977.20.5691. Disponível em: https://www.journals.vu.lt/problemos/article/view/5691.. Acesso em: 29 apr. 2024.