Reference for Yevamot 178:13
ומיטמא לה והא הכא דמדאורייתא אביה מיטמא לה ומדרבנן מיטמא לה בעל משום דהויא לה מת מצוה
Now, what relation is there between Heads and Fathers? But [this has the purpose] of telling you that as fathers may distribute as an inheritance to their children whatever they wish, so may the heads distribute as an inheritance to the people whatever they wish. 'He may defile himself for her'. But, surely, by Pentateuchal law it is her father who may here defile himself for her, and yet it is the husband who by a Rabbinical law was allowed to defile himself for her!<span class="x" onmousemove="('comment',' How then could it be maintained that Beth din has no authority to abrogate Pentateuchal laws? ');"><sup>37</sup></span> — [This was allowed] because she is a meth mizwah.<span class="x" onmousemove="('comment',' Lit., 'dead of the commandment', a corpse in which no one is interested and the burial of which is obligatory upon any person who discovers it. ');"><sup>38</sup></span>