《资治通鉴·唐纪·唐纪五十一》
程怀直的堂兄程怀信担任兵马使，趁着大家心怀不满，便关闭城门，不让程怀直进城，程怀直只好逃回京城。
怀直从父兄怀信为兵马使，因众心之怨，闭门拒之，怀直奔归京师。
Cheng Huaizhi's cousin Cheng Huaixin was appointed as the military commissioner, and he took advantage of everyone's dissatisfaction to close the city gate and prevented Cheng Huaizhi from entering the city. Cheng Huaizhi had no choice but to flee back to the imperial city.