《资治通鉴·宋纪·宋纪六》
拓跋焘刚走了一百多里，就收到古弼的奏表说： 今年秋天谷穗下垂而且颜色金黄，桑麻大豆遍布在田野里，野猪野鹿偷吃，飞鸟大雁啄食，加之风吹雨打，这样损耗早晚就会相差三倍。
行百馀里，得弼表曰： 今秋谷悬黄，麻菽布野，猪鹿窃食；鸟雁侵费，风雨所耗，朝夕三倍。
Tuoba Tao had only travelled over 100 li when he received a memorial from Gu Bi stating: "This autumn, the grains are full and golden, and the fields are covered with mulberry, hemp, and soybeans. However, wild boar, elk, and birds are eating them, and the wind and rain are damaging them. If this continues, the losses will triple.