. [If there were] three brothers, [and] two of them were married to two sisters, while one was married to a stranger; [if] the husband of one of the sisters died, and the one married to the stranger married his wife, and the wife of the second one [then] died, and then the one married to the stranger died —- she is forbidden to him forever, since she was once forbidden to him.  [If there were] three brothers, [and] two of them were married to two sisters, while one was married to a stranger; [if] the husband of one of the sisters divorced his wife, and [then] the one [who was] married to the stranger died, and the divorced [brother] married her and [then] died —- about this it was said: If any of them died or were divorced, their co-wives are permitted.

. If any of them had been the subject of a questionable betrothal or divorce, the co-wives require chalitzah but may not be taken in yibum. How is it that the betrothal was in question? [If] he threw the betrothal to her, and there is a doubt as to whether it was closer to him or closer to her —- this is a questionable betrothal. [How is it that] the divorce was in question? [If] he wrote [a bill of divorce] in his own hand but without witnesses, or with witnesses but without a date, or with a date but with only one witness —- this is a questionable divorce.