TCVN - QCVN 13:2018/BXD
01/03/21
https://file.hstatic.net/1000125203/file/qcvn_13_quy_chuan_ky_thuat_quoc_gia_ve_gara_o-to_4598ebe7e49c4fcc857d87aa18c253db.pdf
https://file.hstatic.net/1000125203/file/qcvn_13_quy_chuan_ky_thuat_quoc_gia_ve_gara_o-to_4598ebe7e49c4fcc857d87aa18c253db.pdf