Zygmunt Kruczek, Adam R. Szromek and Peter Čuka, “Application of the Mystery Shopping Method in Quality Assessment of Tourist Attractions Based on a Survey of Museums in Krakow,” Proceedings of the 25th International Business Information Management Association (IBIMA), ISBN: 978-0-9860419-4-5, 7-8 May 2015, Amsterdam, Netherlands, p. 218-230.