1. Great Universal Encyclopedia, PWN, Warsaw, vol 12, p 251 (1969) (in Polish)
2. Xodo, D.: Multi-participant decision making and balanced scorecard collaborative. In: Rivero, L.C., et al. (eds.) Encyclopedia of database technologies and applications. Idea Group Reference, Hershey (2006)
3. Pawlak, Z.: Knowledge and rough sets. In: Traczyk, W. (ed.) Artificial intelligence problems. Wiedza i Życie, Warsaw (1995) (in Polish)
4. Kulikowski, J.L.: Decision making in a modified version of topological logic. In: Proc. Seminar on Nonconventional Problems of Optimization. Part 1, Prace IBS PAN, 134, Warsaw (1986)
5. Goldman, S.: Information theory. Constable and Co., London (1953)