《资治通鉴·魏纪·魏纪一》
文帝对侍中苏则说： 以前攻破酒泉、张掖的时候，西域瘟派使臣至敦煌，贡献直径一寸的大珍珠，可否再让他们来习卖而得？ 
帝谓侍中苏则曰： 前破酒泉、张掖，西域通使敦煌，献径寸大珠，可复求市益得不？ 
Emperor Wen said to the attendant Su Ze: When we occupied Jiuquan and Zhangye, envoys from the western regions came to Dunhuang and offered large pearls that were one inch in diameter, can we ask them to continue to come to sell and get them?