FERENCZ, Vojtech et al. The Implementation of Knowledge-intensive Services in Drawing out and Bottling of Natural Mineral Water. - Registrovaný: Web of Science, Registrovaný: Scopus. In Acta Montanistica Slovaca. - Košice : Technical University of Košice. ISSN 1335-1788, 2015, vol. 20, no. 2, pp. 125-140 online.