《旧唐书·列传·卷九十二》
加上每支军队中都派有一名宦官做监军，尽挑选骁勇健壮的士兵保卫自己，瘦弱怯懦的上阵作战，因此大多奔逃败北。
复又每军遣内官一人监军，悉选骁健者自卫，羸懦者即战，以是屡多奔北。
In addition, every army had a eunuch dispatched as a supervisor. They chose only brave and robust soldiers to protect themselves, so that the thin, timid ones were sent to fight on the battlefield. As a result, most of them took to flight and were defeated.