Text and Data Mining valid from 2018-10-04
Received: 28 May 2018
Accepted: 20 September 2018
First Online: 4 October 2018
Compliance with ethical standards
: This study was supported by grants VEGA 1/0729/16 and NKFIH K 120118.
: The authors declare that they have no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.