One who brings a bill of divorce from overseas and says, “It was written before me and signed before me,” may not marry the wife. [If he declares,] “He died,” “I killed him,” “we killed him,” he may not marry the wife. R' Yehudah says: [If he declares,] “I killed him,” his wife may not marry; “We killed him,” his wife may marry.

A sage who prohibited a woman to her husband because of a vow may not marry her. [However, if] she refused or performed chalitzah before him, he may marry her, since he is [in] a court. [If] any of these had wives who [later] died, they are permitted to marry them. And if any of these married others and were [then] divorced or widowed, they are permitted to marry them. All of these are permitted to their sons or their brothers.

[If there were] four brothers, [and] two of them were married to two sisters, and those married to the sisters died —- they require chalitzah but may not be taken in yibum; if they went ahead and married [them], they must divorce [them]. R' Eliezer says: Beis Shammai say they may keep [them], but Beis Hillel say they must divorce [them].

[If] one of them was forbidden to one [of the brothers] by the ervah prohibition, he is forbidden to her but permitted to her sister, while the second [brother] is forbidden to both. [If it was] a prohibition by commandment or because of sanctity, she requires chalitzah, but may not be taken in yibum.