JUREK, Witold. On Mathematical Approach to Economic Problems. Studia Oeconomica Posnaniensia, Poznan, Polska, v. 1, n. 1, p. s. 28–39, 2013. DOI: 10.18559/29pwsm57. Disponível em: https://journals.ue.poznan.pl/soep/article/view/3131. Acesso em: 3 sep. 2026.