The following links help with finding sheet music, research findings on the voice or online ear training:

• CVT-Workshop
  Introduction and masterclass with Judith Biedermann and Martina Rick in Basel and Oberägeri
• Complete Vocal Institute
  Information about the method, training possibilities and research about the voice (in English)
• Theta Music Trainer
  Lots of amusing and interactive ear training games to test and improve one’s ear and musical knowledge (in English)
• Musica
  Easily learn to read music online. (in German)
• Sheetmusicplus
  Order music online or print out directly. Affordable prices (in English)
• Musicnotes
  Order music online or print out directly. Affordable prices (in English)
• Les Arts Scéniques
  Martina Rick’s theater group & school: performances, acting classes and more
• CJD Schule Schlaffhorst-Andersen
  Training course in Germany to obtain a degree as a Breath/Speech/Voice Teacher