onto the underside of the instrument and then rests on the chair seat between the player's legs. Adjustable rods have also been developed by Jeff Amos. Other manufacturers have added a left hand thumb support called a crutch, which helps some players with physical control of the instrument. Dutch flute maker Eva Kingma has created a vertical design for the bass flute which allows the weight of the instrument to be supported by the floor. Repertoire Many composers are beginning to write more pieces for the bass flute. These include Katherine Hoover's Two for Two, Bill Douglas's Karuna, Sophie Lacaze's Archelogos II, Mike Mower's Obstinato and Scareso, Gary Schocker's A Small Sonata for a Large Flute, Lorenzo Ferrero's Ellipse and Shadow Lines, Sonny Burnett's Stone Suite, Catherine McMichael's Baikal Journey and Ennio Morricone's Secrets of the Sahara. Other important works include Tristan Murail's Ethers for solo bass flute and small ensemble, Brian Ferneyhough's Mnemosyne for bass flute and tape, Mario Lavista's Lamento a la muerte de Raúl Lavista for solo bass flute, Michael Oliva's Moss Garden also for bass flute and tape, John Palmer's Inwards for bass flute and live-electronics, She Cried by Shiva Feshareki, and Marc Tweedie's Zoli, written for renowned flautist Carla Rees. Studies and concert etudes are beginning to appear that address the instrument's many challenges (physical balance, finger technique, air stream, overblowing, etc.). Low flute specialist Peter Sheridan has commissioned and arranged new compositions in this area, including a set of 'Etudes for Low Flutes' by Hilary Taggart. The sixth movement of Claude Bolling's suite for Flute and Jazz Trio, 'Versatile' has the soloist playing the opening melody on a bass flute. Morton Feldman's composition "Crippled Symmetry" has a part for the bass flute, as does John Cage's late work "Seven2". Hans Pfitzner's 1917 opera Palestrina features an early (true) C bass flute part. Another piece featuring the bass flute is John Mackey's "The Frozen Cathedral" (2013) in two separate sections of the piece. For an extensive list of repertoire for bass flute and contrabass flute see Repertoire Catalogue for Piccolo, Alto Flute and Bass Flute (2004) by Peter van Munster (Roma: Riverberi Sonori). Selected repertoire graded into ability levels with short descriptions and information about basses can be found in The Alto and Bass Flute Resource Guide published by Falls House Press, and specialist low flutes publishing company Tetractys has a growing catalogue of works