Is it permissible for a man to marry his wife's younger sister after her death?

It is forbidden to combine two sisters [in marriage], or a woman and her paternal aunt, or a woman and her maternal aunt. If a man's wife dies, or he divorces her and her waiting period (iddah) ends, it becomes permissible for him to marry her sister, or her paternal aunt, or her maternal aunt, because the impediment—which is combining unmarriageable kin (mahārim) at the same time—is removed.