KOLYADA, A.; REVINSKI, V.; TIKHONENKO, M. Direction field of fingerprint image and its optimization with the help of relaxation procedures. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 3, p. 101–105, 2003. Disponível em: https://studmath.uken.krakow.pl/article/view/13474. Acesso em: 30 oct. 2026.