Recent research has shown that Cage may have met Tudor almost a decade earlier, in 1942, through Jean Erdman: Gann, Kyle (2008). "Cleaning Up a Life". artsjournal.com. Dicapai pada August 4, 2009.
Piekut, Benjamin (December 2014). "Indeterminacy, Free Improvisation, and the Mixed Avant-Garde". Journal of the American Musicological Society. 67 (3): 769–824. doi:10.1525/jams.2014.67.3.769.
Mikawa, Makoto (2015). "The theatricalisation of Mauricio Kagel's 'Antithese' (1962) and its development in collaboration with Alfred Feussner". The Musical Times. 156 (1932): 81–90. JSTOR24615812.