Aleksanyan, S. R. “ON PROOF NORMAL FORMS FOR SOME SYSTEMS OF CLASSICAL PROPOSITIONAL LOGIC”. Proceedings of the YSU A: Physical and Mathematical Sciences 41, no. 1 (212) (March 5, 2007): 38–45. Accessed November 27, 2024. https://journals.ysu.am/index.php/proceedings-phys-math/article/view/vol47_no1_2007_pp038-045.