БІЛЕЦЬКИЙ, Є. А. Walsh functions and Gray codes. Ukrainian Information Security Research Journal, [S. l.], v. 15, n. 2, p. 104–114, 2013. DOI: 10.18372/2410-7840.15.4774. Disponível em: https://jrnl.nau.edu.ua/index.php/ZI/article/view/4774. Acesso em: 21 feb. 2026.