Power engineering 2018. Renewable Energy Sources 2018 : 7th International Scientific Conference. Tatranské Matliare, Slovakia. June 5-7, 2018 - Cirák, Július, 1953-; Perný, Milan, 1985-; Kováč, Zoltán, 1986-; Farkas Smitková, Miroslava, 1977-; Martins, Florinda (Slovak University of Technology, 2018)