Catholic Sources Which Point to the Three Visitors to Abraham in Gen. 18 as The Holy Trinity?

Most of the commentary that I have read regarding the identities of the Three Visitors to Abraham in Genesis 18 have all agreed that God (without specifying which Person) was one of them. Many seem to think that the other two visitors were angels. However, I have seen it indicated that "The three visitors are considered by some to represent the Trinity." (cf. *Understanding the Scriptures* by Scott Hahn) Does anyone know of any Catholic sources (perhaps, Church Fathers, Catholic Saints, papal documents, etc.) which suggest that the aforementioned Three Visitors to Abraham were indeed, the Holy Trinity?