If your CustomTrigger stores references to any other adTempus objects in its custom object data, you must add those objects to this collection so that adTempus knows about them and can enforce referential integrity constraints. 

For example, if your CustomTrigger uses a CredentialProfile, you must add that profile to ReferencedObjects so that adTempus will know that the CredentialProfile is in use and prevent it from being deleted.