《北史·列传·卷十一》
李世哲想取宠于于忠，私下用金帛贿赂章初瞔、杨保元，两人和他交谈之后，引为心腹之交。于忠擅权进官任崇训宫卫尉，也是李世哲的主意。于谨字思敬，小名巨引。为人深沉而有见识，略略浏览一些经籍史书，特别爱好《孙子兵法》。
谨字思敬，小名巨引。沈深有识量，略窥经史，尤好《孙子》兵书。
Li Shizhe wanted to win favor with Yu Zhong, so he privately bribed Zhang Chuzuan and Yang Baoyuan with gold and silk. After the two talked to him, they took him as a confidant. Yu Zhong’s rise to power to the position of Chongxun Palace Guard was also Li Shizhe’s idea. Yu Jin, courtesy name Sixing, nickname Juyin. He is a man of depth and vision, who has read some classics and history books, and is particularly fond of the Art of War.