Reference for Yevamot 26:11
תינח היכא דנשא מת ואחר כך נשא חי לא אתי איסור אחות אשה וחייל אאיסור אשת אח אלא נשא חי ואחר כך נשא מת אחות אשה קדים
midbarah.<span class="x" onmousemove="('comment',' 'To [H] (wilderness or place-name) [H] (I Chron. V, 9). ');"><sup>31</sup></span> Whence do Beth Shammai derive the deduction made by Rab Judah in the name of Rab? — It is derived from Unto one not of his kin.<span class="x" onmousemove="('comment',' Deut. XXV, 5. ');"><sup>32</sup></span> Then let Beth Hillel also derive it from 'Unto one not of his kin'! — This is so indeed. What need, then, was there for 'huzah'? — To include one who was only betrothed.<span class="x" onmousemove="('comment',' To the deceased brother. Such a widow also is subject to the levirate marriage as if she had been actually married. 'Huzah' implies (cf. supra p. 68, n. 3) 'outside', i.e., one who is not within the marriage bond. ');"><sup>33</sup></span>