1. Isabelle Foundation & Certification (2015). https://lists.cam.ac.uk/pipermail/cl-isabelle-users/2015-September/thread.html
2. Conservativity of HOL constant and type definitions (2016). https://sourceforge.net/p/hol/mailman/message/35448054/
3. The HOL system logic (2016). https://sourceforge.net/projects/hol/files/hol/kananaskis-10/kananaskis-10-logic.pdf
4. Type definitions in Isabelle; article “A Consistent Foundation for Isabelle/HOL” by Kunčar/Popescu (2016). https://lists.cam.ac.uk/pipermail/cl-isabelle-users/2016-August/thread.html
5. Arthan, R.: On definitions of constants and types in HOL. J. Autom. Reason. 56(3), 205–219 (2016)