26. 1. 2019 na TA3:
https://www.ta3.com/clanok/1146773/studio-ta3-analyticka-p-fridrichova-o-metodach-vyucby.html?fbclid=IwAR1XP1Gwfb75l9nCa4_Ytk9JvFGC-EVI505KziPTimLi5xsW1Ini0zvW3pw