1. Caramello, O.: The unification of Mathematics via Topos Theory, arXiv: http://arxiv.org/abs/math.CT/1006.3930v1
2. Caramello, O.: Extensions of flat functors and theories of presheaf type, arXiv: http://arxiv.org/abs/math.CT/1404.4610v1 , to appear in a book for Oxford University Press provisionally entitled Lattices of theories (2015)
3. Connes, A.: Cohomologie cyclique et foncteur E x t n . C.R. Acad. Sci. Paris, Sér. I Math. 296, 953–958 (1983)
4. Connes, A., Consani, C.: Cyclic homology, Serre’s local factors and the λ-operations, arXiv: http://arxiv.org/abs/math.AG/1211.4239v1
5. Connes, A., Consani, C.: Cyclic structures and the topos of simplicial sets. Journal of Pure and Applied Algebra 219(4), 1211–1235 (2015)