《宋书·志·卷十八》
殷代有山车，为天下太乎的瑞应之物，称为桑根车，殷人作为天子乘的车。
殷有山车之瑞，谓桑根车，殷人制为大路。
In the Yin Dynasty, there was a mountain car, a sign of auspiciousness for the greatest in the world, called the Sang Gen car, which the Yin people used as the emperor's car.