Reference for Yevamot 104:10
אמר רב יוסף מ"ט דרבי עשאוה כעודר בנכסי הגר וכסבור שלו הן דלא קני
but if he betrothed her for levirate union,<span class="x" onmousemove="('comment',' By addressing to her a ma'amar. ');"><sup>28</sup></span> there is no validity in any such act after the <i>halizah</i>.<span class="x" onmousemove="('comment',' The halizah having severed the levirate bond, there is no room any more for the levirate betrothal. The action of any levir using it is consequently null and void. ');"><sup>29</sup></span> It was taught elsewhere: If a man submitted to <i>halizah</i> from his sister-in-law and then betrothed her, Rabbi said, 'If he betrothed her as in ordinary matrimony it is necessary for her to obtain from him a letter of divorce, but if as for a levirate union there is no need for her to obtain from him a letter of divorce'. The Sages, however, said: 'Whether he betrothed her as in ordinary matrimony or as for the levirate union it is necessary for her to obtain from him a letter of divorce'.