Alonderis Romas, and Pliuškevičius Regimantas. “Cut, Invariant Rule, and Loop-Check Free Sequent Calculus for PLTL”. Lietuvos matematikos rinkinys 52, no. proc. LMS (December 15, 2011): 231–236. Accessed June 27, 2022. https://www.journals.vu.lt/LMR/article/view/15430.