《晋书·列传·第二章》
如果嫌没有明文规定，就有疑问之处从重服丧，我们认为应该与为祖母服丧相同，服齐衰三年。 
若嫌明文不存，则疑斯从重，谓应同于为祖母后齐衰三年。 
If you find it questionable due to the lack of explicit provisions, we believe that they should wear mourning clothes similar to those worn when mourning for a grandmother, and observe a mourning period of three years in coarse sackcloth. 