Reference for Ketubot 187:13

אתמר ב' שטרות היוצאים ביום אחד רב אמר חולקין ושמואל אמר שודא דדייני

It was stated: Two deeds bearing the same date: Rav said: They should be divided [between the two claimants], and Shmuel said: [The case is to be decided at] the discretion of the judges.

Jastrow