1. The concept of multi-level marketing
:SOCHA, Luboš et al. The concept of multi-level marketing. In Marketing management, trade, financial and social aspects of business. International scientific conference. Marketing management, trade, financial and social aspects of business : conference proceedings of the 4th international scientific conference : october 20 - 21, 2016, Košice, Slovak Republic. - Košice : Faculty of Business Economics with seat in Košice, 2016. ISBN 978-80-225-4293-7, s. 218-226 online.