First-Order Logic (Dover Books on Mathematics), Raymond M. Smullyan, Good Book

Calculus of Variations (Dover Books on Mathematics) - Paperback - GOOD

What is Mathematical Logic? (Dover Books on Mathematics) - Paperback - GOOD

First-Order Logic by Smullyan, Raymond M.

Introductory Graph Theory (Dover Books on Mathematics) - Paperback - VERY GOOD

First Order Mathematical Logic (Dover Books on Mathematics) - Paperback - GOOD

Geometry: A Comprehensive Course (Dover Books on Mathematics) - Paperback - GOOD

What is Mathematical Logic (Dover Books on Mathematics) - Paperback - VERY GOOD