Are there any consolidated teachings from the side of Catholic Church on Guardian Angels?

The belief in one having a Guardian Angel is a part of Catholic faith. There are also prayers addressed to the Guardian Angel eg. in preparation of Confession and for protection during one's sleep. Though there are a number of references in the Old Testament and New Testament of angels assisting human beings on specific occasions, the belief on permanent accompaniment of a Guardian Angel to a person, seems to have come up as a later addition. My question therefore is: **Are there any consolidated teachings from the side of Catholic Church on Guardian Angels?**