A. Chubaryan and A. Chubaryan, “Definition of Strong Equality of Tautologies and Universal System for Various Propositional Logics”, Armen.J.Math., vol. 1, no. 2, pp. pp. 30–36, Oct. 2008, Accessed: Apr. 03, 2025. [Online]. Available: https://armjmath.sci.am/index.php/ajm/article/view/25