15 books • 6 series
Book #4: [Auschwitz]
Book #9: Dr. Quasar
Book #2: Linear Algebra Equations and Formulas Cheat Sheet
Book #1: GRE Story Books - Part A.1
Book #1: JJ's Cheat Sheets
Book #1: College Algebra Formulas and Equations Cheat Sheet
Book #1: Prep-Course
Book #1: The Prep-Course for Calculus I
Book #4: Prep Course for College Calculus