Reference for Yevamot 20:10

ועלה דידה הוא דקאי בלא יבנה הא צרה כדקיימי קיימי

In the case of the rival,<span class="x" onmousemove="('comment',' Of a haluzah (v. previous note). A rival is exempt from halizah and the levirate marriage by the action of the haluzah. ');">²⁶</span> both he<span class="x" onmousemove="('comment',' The levir who participated in the halizah. ');">²⁷</span> and the other brothers are subject to <i>kareth</i> for a rival.<span class="x" onmousemove="('comment',' V. infra 53a. ');">²⁸</span>

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