I have used the old encyclopedia profitably on aspects of Roman Catholic devotion, primarily skeptical "Bollandist" articles from Fr. Gregory Thurston. He upset critics who thought he had debunked too many of their favourite devotions and their divine origin (eg. Brown Scapular, Rosary). One author noted he was silent on the Sacred Heart of Jesus, which probably would have upset his Jesuit superiors, whose order was a promoter of the devotion.
Once, after visiting a Greek Orthodox church in London, Ontario, I felt the need to look up information on the Rite of Constantinople. I wonder if this passes muster at all. It's also Fortescue...http://www.newadvent.org/cathen/04312d.htm
I was curious enough to do some reading on the various Latin, Gallican and Mozaribic rites as well .
I had never read up on many of the other Byzantine topics in the Encyclopedia, but the section on Ukrainian Catholics made it clear that the Pope of Rome was not their Patriarch and that, by virtue of their separation from the Orthodox, they had no patriarch of their own either.