Ketubot 98: Widows' Sales

When a sale (a woman selling her late husband's property, for example) takes place outside of the court, does she need to an oath? Does she need to make a public announcement? Can she simply go ahead and sell the property? Also, a new mishnah: a widow whose ketubah is worth however much its worth - when she sells property, the value she attains is her ketubah. But if she overshoots the value of the ketubah, the sale may be null and void (or, according to other opinions, she gives the sum back - or rather, to the heirs).