《汉书·纪·成帝纪》
原先居于桂宫，元帝有时紧急召见，太子出龙楼门，不敢横穿天子所行的驰道，西至直城门，到城门前才横穿以过，又回头到作室门。
初居桂宫，上尝急召，太子出龙楼门，不敢绝驰道，西至直城门，得绝乃度，还入作室门。
He originally lived in Guigong Palace. Emperor Yuan sometimes urgently summoned him. The crown prince exited from the Dragon Tower Gate and dared not cross the imperial road. Instead, he went west to the Straight City Gate and crossed the road in front of the city gate to reach the studio gate.