CHATHAM, R. DOUGLAS; FRICKE, GERD H.; SKAGGS, R. DUANE. The Queens separation problem. Utilitas Mathematica , [S. l.], v. 69, 2006. Disponível em: https://utilitasmathematica.com/index.php/Index/article/view/434. Acesso em: 8 may. 2026.