《晋书·列传·第十章》
至于周朝的公旦，汉代的萧何，或者预先确定嫡长子，或给元妃封爵，都是尊重显示他们的功勋，不同于常例。
至于周之公旦，汉之萧何，或豫建元子，或封爵元妃，盖尊显勋庸，不同常例。
As for Duke Dan of Zhou in the Zhou dynasty and Xiao He in the Han dynasty, either the eldest son of the main wife was designated in advance as heir or the mother of the firstborn son was given a fiefdom, in recognition of their contributions, as an exception to the usual rule.