BURGER A.P.; GROBLER P.J.P.; NIEUWOUDT I.; VAN VUUREN J.H. On an open problem in defective graph colourings. Utilitas Mathematica , [S. l.], v. 76, 2008. Disponível em: https://utilitasmathematica.com/index.php/Index/article/view/557. Acesso em: 8 may. 2026.