V\u0103n m\u1eabu t\u1eadp 2: Ph\u00e2n t\u00edch \u0111o\u1ea1n tr\u00edch Ng\u01b0\u1eddi c\u1ea7m quy\u1ec1n kh\u00f4i ph\u1ee5c uy quy\u1ec1n (B\u00e0i 1)<\/a><\/blockquote><\/iframe>