HUDEC, Miroslav - TORRES VAN GRINSVEN, Vanessa. Business' participants motivation in official surveys by fuzzy logic. In Eurasian Multidisciplinary Forum, EMF 2013 : proceedings vol.1, 24-26 October 2013, Tbilisi, Georgia. - Kocani : European Scientific Institute, 2013. ISBN 978-608-4642-10-7, p. 42-52.