1. Goldblatt, R.: The Categorial Analysis of Logic. Studies in Logic and the Foundations of Mathematics, vol. 98, revised ed., p. XVI. Elsevier Science Publishers, Amsterdam, The Netherlands (1984)
2. Wong, C.K.: Covering Properties of Fuzzy Topological Spaces. J. Math. Anal. Appl. 43, 697–704 (1973)
3. Perkins, D.: The Eureka Effect. The Art and Logic of Breakthrough Thinking. Norton, New York, London (2001)
4. Gigerenzer, G.: Gut Feelings. The Intelligence of the Unconscious. Viking, London (2007)
5. Raikov, A.N.: Holistic Discourse in the Network Cognitive Modeling. J. Math. Fundam. Sci. 3, 519–530 (2013)