《宋史·列传·卷二百三十》
蔡京和太宰郑居中不合，郑居中因遭家丧而离职，蔡京怕他被重新起用，郑居中是王王圭的女婿。
京与太宰郑居中不相能，居中以忧去，京惧其复用，而居中，王珪婿也。
Cai Jing didn't get along with Zheng Juzhong, the Grand Secretary. Zheng Juzhong once left his position because of his family's mourning. Cai Jing was afraid that he would be reinstated. Zheng Juzhong was the son-in-law of Wang Wanggui.