4 Textbooks

1. Spiegel, Murray R. Vector Analysis Schaum's Outline Series (McGraw-Hill) 1959. ISBN 07-060228-X.
   or
   Spiegel, Murray S., Lipschutz, Seymour, & Spellman, Dennis, Vector Analysis Schaum's Outline Series (McGraw-Hill) 2nd Ed 2009. ISBN 978-0-07-161545-7.

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.)

References:

1. Advanced Engineering Mathematics by Peter V. O'Neil. Thomson-Engineering; 6th edition, 2007. ISBN: 0-534-55208-0.