Funding for this research was provided by:
National Science Centre, Poland (2016/20/T/NZ4/00525, 2013/09/D/NZ4/01692, 2016/23/N/NZ4/03228)
Text and Data Mining valid from 2018-05-29
Received: 6 April 2018
Accepted: 1 May 2018
First Online: 29 May 2018
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