. "Sino-Vietnamese borders" . . . "all border crossings with China" . "China\u2013Vietnam border" . "border with Vietnam" . "Vietnamese border" . . . . . "China\u2013Vietnam" . "northern border" . "bordering" . "China-Vietnam border" . "China\u2013Vietnam border" . . "border" . "China and Vietnam share a border" . . . . "buffer zone with China" . "two countries' border" . . "the border" . . "Sino-Vietnamese border" . "their border dispute" . .