blue book

noun

1. an official government report or registry, often having a blue cover
2. ☆ a book listing people who are socially prominent
3. ☆ a blank booklet with a blue paper cover, in which students can write examination answers
4. ☆

   Etymology: < Kelley Blue Book, trademark for automotive price guides

   a book, online guide, etc. listing market values of used goods, collectibles, etc., esp. one listing such values of used vehicles