《智囊(选录)·察智部·赵广汉》
例如想要知道马的价钱的时候，就先打听够的价钱，然后再问牛羊的价钱，到最后才问马的价钱。因为彼此互问的结果，便能打听出比较可靠的标准行情，到最后就能够真正知道的价钱。
钩距者，设欲知马价，则先问狗，已问羊，又问牛，然后及马，参伍④其价，以类相准，则知马之贵贱，不失实矣。
For example, when you want to know the price of a horse, first ask about the price of enough money, then ask about the price of cattle and sheep, and finally ask about the price of a horse. Because of the mutual inquiries, you can find out the relatively reliable standard market price, and finally you can know the real price.