Nikolova, S. (1998) “$\prod_{1}^{0}$-POSITIVE INDUCTIVE DEFINABILITY ON ABSTRACT STRUCTURES”, Ann. Sofia Univ. Fac. Math. and Inf, 90, pp. 91–108. Available at: https://stipendii.uni-sofia.bg/index.php/fmi/article/view/288 (Accessed: 24 November 2024).