《资治通鉴·晋纪·晋纪三十四》
但是，我的父亲杜雄，年龄已经过了六十岁，我请求陛下能给他一个做本县县令的俸禄，这样，才可以代我表明象乌鸦反哺那样的孝敬父母的心情。 
臣父雄年逾六十，乞本县之禄以申乌鸟之情。 
“But my father, Du Xiong, is now over sixty years old. I ask Your Majesty to grant him the salary of a local prefect—so that I may show my reverence for my parents, like a raven feeding its parents.”