More information about this theme you will find on the Internet on following homepages:
GEMA: http://www.gema.de
JOSEF KELLER VERLAG http://www.keller-verlag.de
MEDIA LINGUA http://www.medialingua.de
MUSICBIZ http://www.musicbiz.de
MEDIENHANBUCH http://www.medienhandbuch.de
VG WORT http://www.vgwort.de