List of quarter tone pieces

A selection of compositions using quarter tones: == A == Thomas Adès Asyla calls for an upright piano tuned a quarter-tone flat. == B == Jan Bach Concert Variations for solo euphonium; "each variation is based on different performance techniques of the instrument, including quarter-tones" János Bali Aiolos ajándéka (Gift of Aiolos) for violin, viola da gamba (tuned 1/4 tone lower), harpsichord (upper manual tuned 1/4 tone lower) Clarence Barlow Çoǧluotobüsişletmesi for four pianos.

Source: Wikipedia — List of quarter tone pieces (CC BY-SA 4.0)