KUKOVÁ, Mária - NAVARA, Mirko. Principles of inclusion and exclusion for fuzzy sets. In Fuzzy Sets and Systems. - Amsterdam : Elsevier B.V., 2013. ISSN 0165-0114, 2013, vol. 232, pp. 98-109. Dostupné na: https://doi.org/0.1016/j.fss.2013.02.014.