** Symmetry and Separation of Variables**

by Willard Miller

Addison-Wesley, Reading, Massachusetts, 1977 (out
of print)

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Chapter 1. The Helmholtz Equation

Chapter 2. The Schrödinger and Heat Equations

Chapter 3. The Three-Variable Helmholtz and Laplace Equations

Chapter 5. The Hypergeometric Function and Its Generalizations

Appendix A. Lie Groups and Algebras

Appendix B. Basic Properties of Special Functions