《明史·志·卷六十八》
后来辽东督师袁崇焕因为缺马，请求在两京州县寄养马内，折合三千匹的价钱从西部边防购买。
既而辽东督师袁崇焕以缺马，请于两京州县寄养马内，折三千匹价买之西边。
Later, Yuan Chonghuan, the chief military commander of Liaodong, because of the shortage of horses, requested to convert the price of 3,000 horses to the west frontier defense to purchase them.