Extensional Concepts in Intensional Type Theory - PhD thesis of Martin Hofmann, which shows how the intensional, constructive view of equality in Martin-Löf's Type Theory can be reconciled with the classical, extensional view of identity. www.dcs.ed.ac.uk/lfcsreps/EXPORT/95/ECS-LFCS-95-327/index.html
Implementing Mathematics Using NuPrl - Full online text of the book. Includes tutorial on Martin-Löf's type theory, motivating remarks on intuitionism, as well as sample formalisations of constructive mathematics in the NuPrl theorem prover. www.cs.cornell.edu/Info/Projects/NuPrl/book/doc.html
Inductive Definitions in Type Theory - Internet resource accompanying a graduate course given by Peter Dybjer. www.cs.chalmers.se/~peterd/kurser/tt/index.html
Nuprl Project Related Web Sites - NuPRL is the oldest theorem prover based on Martin-Löf's Type Theory. www.cs.cornell.edu/Info/Projects/NuPrl/html/publication.html
Research Profile of Anton Setzer - Anton Setzer is a prominent researcher working in the area of characterising strong predicative universes in Martin-Löf's Type Theory. www.math.uu.se/~setzer/research/researchprofile.html