Composer Christopher Tarnow has been collaborating with Carolina Eyck since 2013. In 2014, the duo released Improvisations for Theremin and Piano with Butterscotch Records. Next month, they will release a new album of sonatas for the theremin on the Genuin label.
In anticipation of the release, Mr. Tarnow has made his sonatas available for purchase. You can find a list of works and purchasing details at http://christophertarnow.com/Werke
Here's a video of one of the works, Sonata For Theremin and Piano: