MANUKIAN, S. N. . On an Algebraic Classification of Multidimensional Recursively Enumerable Sets Expressible in Formal Arithmetical Systems. Mathematical Problems of Computer Science, [S. l.], v. 41, p. 103–113, 2021. Disponível em: http://mpcs.sci.am/index.php/mpcs/article/view/238. Acesso em: 18 may. 2024.