Reference for Yevamot 214:9

מדקא אכיל פירי פשיטא נשואה היא והאמרי ב"ש נשואה לא ממאנה תרי קיטרי עבדו ביה:

made a declaration of refusal against one [levir] she is permitted [to marry] even him. May it be assumed that he is of the same opinion as R. Oshaia who maintains that a minor has no right to make a declaration of refusal in respect of his levirate bond?<span class="x" onmousemove="('comment',' And if she did exercise It she still remains permitted to the levir, v. supra p. 741, n. 8. ');">²³</span> — In respect of one levir she may well be entitled to annul [the levirate bond]; here, however, we are dealing with two levirs [the reason<span class="x" onmousemove="('comment',' For the invalidity of the mi'un. ');">²⁴</span> being] that no declaration of refusal is valid against half a levirate bond.<span class="x" onmousemove="('comment',' She is equally bound to the two levirs, and her refusal was declared against one of them only. ');">²⁵</span> When Rabin came<span class="x" onmousemove="('comment',' From Palestine to Babylon. ');">²⁶</span>

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