《资治通鉴·晋纪·晋纪三十二》
这时，东晋朝廷内外疑虑纷纷，交通阻塞，水陆关卡林立，形势危急而严峻。殷仲堪用斜纹的绢绸给王恭写了一封书信，藏在箭杆之中，然后装上箭头，涂上油漆，托庾楷转交给王恭，王恭打开信，因为绢的角上抽丝，不再能确切地辨出是殷仲堪的亲笔手书，怀疑此信是庾楷伪造的，况且想到去年讨伐王国宝时，殷仲堪曾经违反期约，按兵不发，这次也一定会同去年一样，因此便先行向都城大举进兵。
时内外疑阻，津逻严急，仲堪以斜绢为书，内箭簳中，合镝漆之，因庾楷以送恭。恭发书，绢文角戾，不复能辨仲堪手书，疑楷诈为之，且谓仲堪去年已违期不赴，今必不动，乃先期举兵。
At this time, there were many doubts inside and outside the Eastern Jin Dynasty court. The traffic was blocked, and there were checkpoints on the water and land routes. The situation was critical and severe. Yin Zhongkan wrote a letter to Wang Gong with the patterned silk and hid it in the arrow shaft. Then, he put on the arrowhead, painted it with paint, and asked Yu Kai to give it to Wang Gong. Wang Gong opened the letter and found that the corner of the silk was drawn out, so he could no longer xác định precisely whether it was Yin Zhongkan's personal handwritten letter and suspected that the letter was forged by Yu Kai. Moreover, he thought that Yin Zhongkan had violated the agreement and did not send troops when he attacked Wang Guobao last year. This time, it would be the same as last year, so he decided to send troops to the capital first.