1. HOL light,
http://www.cl.cam.ac.uk/~jrh13/hol-light
2. Proofscape,
http://proofscape.org
3. Prooftree,
http://askra.de/software/prooftree/
4. Adams, M.: Tactician (2012),
http://www.proof-technologies.com/tactician
5. Adams, M., Aspinall, D.: Recording and refactoring HOL light tactic proofs. In: Workshop on Automated Theory eXploration (2012)