《史记·三十世家·管蔡世家》
六年，曹国有个农夫公孙强也喜好射猎，猎得白雁献给伯阳，大谈射猎之道，借此商问政事。
六年，曹野人公孙强亦好田弋，获白雁而献之，且言田弋之说，因访政事。
Six years later, a farmer named Gongsun Qiang in the State of Cao also preferred hunting, he hunted a swan and presented it to Boyang. Taking this opportunity, he proposed a way of hunting and talk about political affairs on the side.