《资治通鉴·唐纪·唐纪六十二》
等到他有病时，请求朝廷批准自己离职赴京。朝廷尚未来得及安排由谁代替他的职务，张已经病重，于是，告诫儿子张元益率全族人返归京城，不准效法河北藩镇的惯例，继承节度使的职务。
及有疾，请入朝，朝廷未及制置，疾甚，戒其子元益举族归朝，毋得效河北故事。
When he fell ill, he requested the court's approval to resign and return to the capital. Before the court had the chance to decide who would replace him, Zhang's illness worsened. He thus ordered his son Zhang Yuanyi to lead the entire family back to the capital and warned him against following the common practice in Hebei藩镇 of inheriting the position of military governor.