1. Anderson, R. 2005. Security protections engineering. WNT, Warsaw.
2. Białas, A. 2007. Information and services security in a modern institution and company. WNT, Warsaw.
3. Denning, D. E. 2002. Information war and information security. WNT, Warsaw.
4. Some Theorems on Abstract Graphs
5. EL Fray, I. 2013. Method for determining confidence in the information system based on the process of risk estimation and management. Thesis. Faculty of Computer Science, West Pomeranian University of Technology.