1. Agda. http://wiki.portal.chalmers.se/agda/ .
2. The Automath Archive. Hosted at Eindhoven University of Technology: http://www.win.tue.nl/automath/ .
3. H. P. Barendregt. Lambda Calculi with Types. Chapter 2 (pp. 117–309) of S. Ambramsky et al. (eds.): Handbook of Logic in Computer Science, Vol. 2, Oxford University Press, 1992.
4. H. Barendregt and H. Geuvers. Proof-Assistants using Dependent Type Systems. Chapter 18 (pp. 1149–1238) of J. A. Robinson and A. Voronkov (eds.): Handbook of Automated Reasoning, Vol. 2, Elsevier and The MIT Press, 2001.
5. L. S. van Benthem Jutting. Checking Landau’s “Grundlagen” in the Automath System. Ph.D. thesis, Technische Hogeschool Eindhoven, 1977.