佛祖歷代通載 2.93

2.93

（二十三）　宋晉衛楚四國成王封（同姓者。長曰伯父。幼曰叔父。異姓者。長曰伯舅。幼曰叔舅）。

(23) King Cheng enfeoffed the four states of Song, Jin, Wei, and Chu. (Those of the same surname: the senior are called paternal senior-uncles, and the junior are called paternal junior-uncles. Those of different surnames: the senior are called maternal senior-uncles, and the junior are called maternal junior-uncles).