PISZCZEK, M. Second Hukuhara derivative and cosine family of linear set-valued functions. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 5, p. 87–98, 2006. Disponível em: https://studmath.uken.krakow.pl/article/view/13295. Acesso em: 31 oct. 2026.