4 Textbooks

1. Spiegel, Murray S. Vector Analysis Schaum's Outline Series (McGraw-Hill) 1959. ISBN 07-060228-X.
2. DuChateau, Paul & Zachmann, David W, Partial Differential Equations Schaum's Outline Series (McGraw-Hill) 1986. ISBN 0-07-017897-6
3. Spiegel, Murray R, & Liu, John, Mathematical HandBook of Formulas and Tables Schaum's Outline Series (McGraw-Hill) 2nd edition 1999. ISBN 0-07-038203-4. (Recommended, but any mathematical handbook is allowed.)