Méndez, José M. “A Routley-Meyer Semantics for Ackermann’s Logics of ‘strenge implication’”. Logic and Logical Philosophy 18, no. 3-4 (March 30, 2010): 191–219. Accessed April 26, 2024. https://apcz.umk.pl/LLP/article/view/LLP.2009.010.