Reference for Yevamot 203:13
אי נמי משום חצי מנעל
a strap also should be tied to it,<span class="x" onmousemove="('comment',' Round the sandal and the foot, prior to the halizah. ');"><sup>28</sup></span> so that the <i>halizah</i> may be properly performed.<span class="x" onmousemove="('comment',' By untying the strap first and then releasing the foot from the shoe, the woman carries out completely the prescribed requirements of the halizah. The rt. [H] may signify both (a) loosing or untying sc. of the shoe strap, and (b) releasing sc. of the foot from the shoe. ');"><sup>29</sup></span> (Mnemonic: <i>You permitted a sister-in-law a sandal</i>.)<span class="x" onmousemove="('comment',' A prominent verb and two prominent nouns in the following three rulings reported by Rab Judah in the name of Rab. ');"><sup>30</sup></span>