MANUKIAN, S. N. On Some Properties of Positive and Strongly Positive Arithmetical Sets. Mathematical Problems of Computer Science, [S. l.], v. 50, p. 52–55, 2021. DOI: 10.51408/1963-0019. Disponível em: http://mpcs.sci.am/index.php/mpcs/article/view/47. Acesso em: 21 apr. 2024.