Authors may choose to publish open access by paying an article publishing charge. Publikacja dostępna także w wersji elektronicznej, brak informacji o licencji. Received 23 November 2017 ; Received in revised form 4 July 2018 ; Accepted 6 July 2018 ; Available online 09 July 2018. The study was supported by the project PROGRES Q36 from the Charles University. |