https://www.neopublic.sk/novinky-na-facebooku/
https://sospreskoly.org/files/schiffer2010.pdf
https://sk.wikipedia.org/wiki/Port%C3%A1l
link na obrázok : https://www.google.sk/search?q=mark+zuckerberg&source=lnms&tbm=isch&sa=X&ei=6SiNUryTEOqJ4gSV1IGYCA&ved=0CAcQ_AUoAQ&biw=1366&bih=666#facrc=_&imgdii=_&imgrc=QXCXenwKeG_TbM%3A%3BGploBHK59OL1xM%3Bhttp%253A%252F%252Fwww.urbansplatter.com%252Fwp-content%252Fuploads%252F2013%252F10%252FMark-Zuckerberg2.jpg%3Bhttp%253A%252F%252Fwww.urbansplatter.com%252Fmark-zuckerbergs-house-palo-alto%252F%3B1334%3B1800
