Reference books on ancient history
I'm not putting this in the books forum because I figure that it'll get more attention here. What reference books do you guys find most useful when looking at classical antiquity? Which one is the best? For example, I use the Oxford Companion to Classical Civilization. It has a lot of good entries on topics on social history, but names, places, and people groups are often lacking. I've heard good things about the Cambridge Dictionary of Classical Civilization, but don't have any personal experience with it. Which reference books are the best?