1. A Cook's Tour of the Finitary Non-Well-Founded Sets;Abramsky,2005
2. On the notion of proposition, truth and set;Aczel,1980
3. Non-well-founded Sets;Aczel,1988
4. P. Apostoli and A. Kanda. Parts of the continuum: towards a modern ontology of science. To appear in The Poznan Studies in the Philosophy of Science and the Humanities, ed. L. Nowak.
5. Approximation spaces of type-free sets;Apostoli,2000