144 Yevamot 5/1-3

(1) Rabban Gamliel says: There is no bill of divorce after a bill of divorce, and there is no Ma’amar [semi-betrothal of a Yevama widow through money or a document] after Ma’amar, and there is no relations after relations, and no Chalitzah [the ceremony releasing the widow of a childless man from the obligation of Levirate marriage] after Chalitzah. And the Sages say: There is a bill of divorce after a bill of divorce, and there is Ma’amar after Ma’amar, but there is nothing after relations and nothing at all after Chalitzah.

(2) How so? [If] one performed Ma’amar for his Yevama [a woman whose husband died childless and whose brother-in-law must marry or dismiss her], and [subsequently] gave her a bill of divorce, she needs to perform Chalitzah for him. If he performed Ma’amar and underwent Chalitzah, she needs [to receive] a bill of divorce from him. If he performed Ma’amar and had relations, he is following the necessary Mitzvah.

(3) [If] one gave her [his Yevama] a bill of divorce, and performed Ma’amar she requires a [second] bill of divorce and Chalitzah. [If] one gave her a bill of divorce and had relations [with her] she requires a [second] bill of divorce and Chalitzah. [If] one gave her a bill of divorce and underwent Chalitzah from her there is nothing at all after Chalitzah. [If] he underwent Chalitzah from her and performed Ma’amar, or [if] he gave her a bill of divorce and had relations with her, or [if] he had relations with her and performed Ma’amar, or [if] he gave her a bill of divorce and underwent Chalitzah from her - there is nothing at all after Chalitzah. This is so with both one Yevama and one Yavam, or two Yevamot and one Yavam.