《资治通鉴·晋纪·晋纪三十二》
张曹为人向来勇武豪健，他请求为慕容宝招募兵众。慕容盛也劝慕容宝暂且留驻在此，观察兰汗的真实想法和动向。
曹素武健，请为宝合众，盛亦劝宝宜且驻留，察汗情状。
Zhang Cao was known for being brave and strong. He requested permission to recruit troops for Murong Bao. Murong Sheng also advised Murong Bao to remain there temporarily and observe Ran Han’s intentions and movements.