Sitografia e fonti web
Siti Ufficiali
http://www.holzer.it/http://www.steko.ch/http://www.steko.ch/en/metanavigation/
home.htmlhttp://www.steko.it/content.asp?
L=1&IdMen=156http://www.steko.cz/newshttp://www.steko.si/
Altri siti
http://www.ecohome-int.com
Video http://www.youtube.com/watch?v=ciL9Xk91XSY&feature=player_embedded#
!http://www.youtube.com/watch?v=JDBJWZnIbNchttp://www.youtube.com/watch?
v=dpeN0seedaw&feature=related