Ujj-Hilliard, Emöke. An Analysis of the Genesis of Motive, Rhythm, and Pitch in the First Movement of the Sonata for Two Pianos and Percussion by Béla Bartók., dissertation, May 2004; (https://digital.library.unt.edu/ark:/67531/metadc4480/m1/1/: accessed May 26, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .