《论衡·卷十三·别通篇》
假使禹和伯益走的地方不远，就不能够写出《山海经》；假使董仲舒和刘子政没有读过《山海经》，也不能解决这二个疑难问题。
使禹、益行地不远，不能作《山海经》；董、刘不读《山海经》，不能定二疑。
If Yu and Boyi had not traveled far, they would not have been able to write the "Classic of Mountains and Seas"; if Dong Zhongshu and Liu Zizheng had not read the "Classic of Mountains and Seas", they would not have been able to solve these two perplexing problems.