HELMAN, Z. Intellekt und Phantasie in der Musik von Witold Lutosławski. Musicological Annual, [S. l.], v. 18, n. 1, p. 69–81, 1982. DOI: 10.4312/mz.18.1.69-81. Disponível em: https://revije.ff.uni-lj.si/MuzikoloskiZbornik/article/view/5126. Acesso em: 19 jun. 2021.