- PER LINDSTRöM, “Provability logic—a short introduction”, Theoria, 62, № 1-2, 1996,
19 
- Robert A. Di Paola, Franco Montagna, complexity, logic, and recursion theory, 2019,
123 - Mirjam de Vos, Rineke Verbrugge, Barteld Kooi, “Solutions to the Knower Paradox in the Light of Haack’s Criteria”, J Philos Logic, 52, № 4, 2023,
1101