《梦溪笔谈·辨证一》
据今天的查考，天成二年是丁亥年，长兴三年是壬辰年，相差五年。
今按，天成四年歳庚寅，长兴三年歳壬辰，计差二年。
According to today's research, the second year of Tiancheng was the year of Dinghai, and the third year of Changxing was the year of Renchen, which was a difference of five years.