1. A final coalgebra theorem;Aczel,1989
2. Non-Well-Founded Sets;Aczel,1988
3. The Russell-Prawitz modality;Aczel;Mathematical Structures in Computer Science,2001
4. Bibliography: Hugh MacColl;Astroh;Nordic Journal of Philosophical Logic,1998
5. Terminal coalgebras in well-founded set theory;Barr;Theoretical Computer Science,1993