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Title: Robots (Scholastic Discover More Reader, Level 2), Author: Gail Tuchman
Title: Mega Machines (DK Readers Level 1 Series), Author: Deborah Lock
Title: Big Machines (Rookie Reader), Author: Melanie Davis Jones
Title: What Is a Pulley?, Author: Lloyd G. Douglas
Title: Simple Machines (Rookie Read-About Science: Physical Science: Previous Editions), Author: Allan Fowler