The document you’re looking for is the CDF’s (February 25, 1978) “Norms of the Congregation for Proceeding in Judging Alleged Apparitions and Revelations.”
The following excerpts are taken from the article “Norms and Process for Judging Private Revelations” (see link below):
"When an allegedly supernatural event has occurred, it is the responsibility of the local bishop to conduct an investigation, usually through a committee of experts.
Theologically and canonically, the bishop is entrusted with the role of “oversight” of the diocese. This role of “oversight” is based on the bishop’s responsibility both for public worship and for the religious teaching which occurs in the diocese.
All such investigations are conducted by the bishop to determine whether public worship should continue to be held in those places. It could happen that the investigative committee could conclude that at this time it is able neither to make a clearly positive nor a clearly negative judgement. If the matter is still being investigated, the bishop could permit public worship, while at the same time continuing to be vigilant that the devotions do not wander into deviant directions.
As the bishops are entrusted with these responsibilities stemming from the nature of their office, so there are fundamental responsibilities on the part of the members of the diocese. First, they are to obey their bishops when the latter act as Christ’s representatives (canon 212), that is, when they teach formally or establish binding discipline as pastors of a particular church. This obedience owed to the bishops in their capacity as leaders of particular churches is intended to promote the common good. Canon 753 also speaks of the “religious assent” owed to the bishops’ teaching authority, which means a special quality of respect and gratitude, along with critical awareness and good will. Hence, there should be intelligent obedience to ecclesiastical authority in the matter of alleged apparitions. "
For complete text (including references) click here.