I've been reading the core rulebook -and loving it-, and planning to run a game soon, and I'm guessing that if there's no mention of more than one attack of opportunity anywhere, it's because a player or foe can make just one in a turn.
If this is the case, is there in other book of the game, a feat or power that changes this? (as Combat Reflexes in Pathfinder).
Or am I missing something in the book? (I just have the core rulebook for now).