ZHANG, GUIZHI; AN, YONGHONG; FENG, TAO. The intersection problem for PBD(4,7). Utilitas Mathematica , [S. l.], v. 113, 2019. Disponível em: https://utilitasmathematica.com/index.php/Index/article/view/1364. Acesso em: 7 may. 2026.