Reference for Yevamot 214:7

כי אתא רבין אמר רבי יוחנן מיאנה בזה מותרת לאחין ולא הודו לו מאן לא הודו לו אמר אביי רב רבא אמר רבי אושעיא ואמרי לה רב אסי:

exercised her right of refusal against one<span class="x" onmousemove="('comment',' The levir who gave her the letter of divorce. ');">²⁰</span> [of the levirs] she is permitted [to marry] the others;<span class="x" onmousemove="('comment',' Lit., 'this'. ');">¹⁷</span> her case being unlike that of the recipient of a letter of divorce.<span class="x" onmousemove="('comment',' From one of the levirs. ');">¹⁸</span> For with the recipient of a letter of divorce<span class="x" onmousemove="('comment',' From one of the levirs. ');">¹⁸</span>

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