- https://en.wikipedia.org/wiki/Main_Page
- http://ebooks.edu.gr/modules/ebook/show.php/DSGL100/418/2817,10618/
- https://www.nasa.gov/
- http://photodentro.edu.gr/edusoft/?locale=el
- http://fouit.gr/2014/08/15/%CF%84%CE%BF-%CF%80%CE%B9%CE%BF-%CF%8C%CE%BC%CE%BF%CF%81%CF%86%CE%BF-%CF%84%CF%81%CE%B1%CE%B3%CE%BF%CF%8D%CE%B4%CE%B9-%CF%84%CE%B7%CF%82-%CE%B3%CE%B7%CF%82-%CE%B2%CE%AF%CE%BD%CF%84%CE%B5%CE%BF/
- http://atheo.gr/%CF%84%CE%BF-%CE%B1%CE%BD%CE%AC%CE%B3%CE%BB%CF%85%CF%86%CE%BF-%CF%84%CE%B7%CF%82-%CE%B3%CE%B7%CF%82/