From: Rabbi Moshe Sofer
To: Unknown recipient
The Chasam Sofer permits the women whose husbands were reported as goseis to remarry, relying on the ruba d'ruba presumption of death after three days and an independent siman muvhak. He also resolves the apparent contradiction between the Beis Yosef's rulings in Even HaEzer and Yoreh Deah, explaining that the three-day goseis rule triggering mourning applies only to non-spousal relatives and does not directly authorize a wife's remarriage.
Source: Shu"t Chasam Sofer EH II §134