[If] there were two sisters-in-law, and each one stated, “My husband died” —- each one is pro- hibited [to marry] because of the other's husband. [If] one had witnesses but the other did not —- the one with witnesses is prohibited [to marry], whereas the one without witnesses is permitted. [If] one had children but the other one did not —- the one with children is permitted [to marry], whereas the one without children is prohibited. [If] they were taken in yibum and their yevamin [then] died, they are prohibited from remarrying. R' Elazar says: Since they were permitted to the yevamin, they are permitted to all men.