To anyone who would like to learn more about the Catholic Church, a good website is www.newadvent.org. They have the Catholic Encyclopedia on line.
New Advent?
The encyclopedia they have on line was written in 1911. It's a great resource for some true facts about antiquity but is not apologetic, and not authoritative, and very alien to Protestantism.
For purely academic sources, the Catechism is much better. Just be sure to actually READ the foot-notes. For instance, just because they cite St. Augustine (rather than directly citing scripture) doesn't mean St. Augustine is the source for the doctrine (and not scripture), but rather that St. Augustine explains it well.
But I'd much more recommend someone like Scott Hahn. Not exactly the magisterium himself, but writes from the perspective of a protestant convert.