1Seif 1
A yabam (brother-in-law) who gives a get (divorce document) to the yevama (sister-in-law) disqualifies her and her co-wives from yibum (levirate marriage) with him and with the other brothers, according to rabbinic law. Any get that disqualifies a wife from marrying a kohen (priest) also disqualifies a yevama from yibum, and she is not permitted to marry a stranger until he performs chalitza (ceremonial release).