Funding for this research was provided by:
European Regional Development Fund (GINOP-2.3.4-15-2016-00004)
Text and Data Mining valid from 2019-11-02
Received: 2 October 2019
Accepted: 26 October 2019
First Online: 2 November 2019
Compliance with ethical standards
: On behalf of all authors, the corresponding author states that there is no conflict of interest.