What did Amanda notice about the confetti?

Amanda noticed that the confetti scraps were cut from the encyclopedia.

But one person wasn't yelling: Amanda Beale. She was holding one of the homemade confetti scraps, gaping at it. Then she was scrambling across the sidewalk, the street, shoving people's legs aside, grabbing more scraps, crying out, "Oh no! ... Oh no!" And then she was running.
Maniac saw. He leaped from the table. He picked up a scrap. There was printing on it, about Africa. He picked up another; this one mentioned ants. Another: Aristotle.
The encyclopedia A!