Ertola Biraben R. J. Michael Dunn and Gary M. Hardegree, "Algebraic Methods in Philosophical Logic", Oxford Logic Guides, no. 41. LLP [Internet]. 2005 Dec. 23 [cited 2025 Jul. 5];14(2):265-7. Available from: https://apcz.umk.pl/LLP/article/view/LLP.2005.017