*[http://www.enjoythemusic.com/superioraudio/equipment/1107/final_sound_1000i.htm enjoythemusic.com – Dick Olsher: »Final Sound 1000i Electrostatic Loudspeaker. An evolution of the electrostatic loudspeaker«] {{engl}}
*[http://www.stereotimes.com/amp060100.shtml stereotimes.com – Frank Alles & Martin Appel: »Innersound Electrostatic Amplifier«] {{engl}}