《史记·七十列传·大宛列传》
自从博望侯因为开辟了通往外国的道路而得到尊官和富贵，以后跟随出使的官吏和士卒都争着上书，陈述外国的珍奇之物、怪异之事和利害之情，要求充当使者。
自博望侯开外国道以尊贵，其後从吏卒皆争上书言外国奇怪利害，求使。
Ever since Marquis Bo Wang was bestowed official rank and wealth for opening a route to foreign lands, officials and soldiers who followed on later missions competed to write memorials, describing the precious and strange objects, the pros and cons, and asking to be sent as envoys.