1 Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia; Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia; Alma Mater Europaea, Slovenska ulica 17, 2000 Maribor, Slovenia.
2 Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia.
3 Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia.
4 Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia; Alma Mater Europaea, Slovenska ulica 17, 2000 Maribor, Slovenia; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404332, Taiwan; Complexity Science Hub Vienna, Josefstädterstrasse 39, 1080 Vienna, Austria. Electronic address: matjaz.perc@gmail.com.