Intuitionistic Topology and Foundations of Constructive Mathematics
- Math page of Frank Waaldijk, containing articles and PhD thesis on foundations of constructive mathematics and intuitionistic topology. Also links to other mathemtaicians in this field.
- http://home.hetnet.nl/~sufra/mathematics.html

Intuitionistic logic
- Wikipedia (free encyclopedia) article.
- http://en.wikipedia.org/wiki/Intuitionistic_logic

Intuitionistic Logic
- A very concise introduction to the subject. Includes overview of the syntax, Kripke models, analytic tableau, natural deduction.
- http://cs.wwc.edu/~aabyan/Logic/Intuitionistic.html

A Bibliography of Constructive Mathematics
- Compiled by Erik Palmgren.
- http://www.math.uu.se/~palmgren/biblio/bib.html

Constructive Mathematics
- Maintained by Fred Richards.
- http://www.math.fau.edu/Richman/html/construc.htm

Confessions of a Formalist, Platonist Intuitionist
- Autobiographical article by Fred Richman, describing his encounter with intuitionism.
- http://www.math.fau.edu/Richman/html/Confess.htm

Porgi
- Porgi is a Proof-Or-Refutation Generator for Intuitionistic propositional logic, implementated by Allen Stoughton. Given a sequent, Porgi either finds a minimally sized, normal natural deduction of the sequent, or it finds a "small", tree-based
- http://www.cis.ksu.edu/~allen/porgi.html