《北史·列传·卷十三》
明元帝生病期间，太武帝主持国政，刘洁与古弼等人被选派服侍皇太子，帮他处理机要大事。
明元寝疾，太武监国，洁与古弼等选侍东宫，对综机要。
During the illness of Emperor Mingyuan, Emperor Taiwu presided over the affairs of the state; Liu Jie and Gu Bi and others were selected to serve the crown prince and help him in his handling of state affairs.