Chubaryan, Anahit A., Armine A. Chubaryan, and Sona R. Aleksanyan. 2021. “Omparison of the Complexities in Frege Proofs With Different Substitution Rules”. Mathematical Problems of Computer Science 30 (December):36-39. http://mpcs.sci.am/index.php/mpcs/article/view/413.