Renardy, M., & Rogers, R. C. (2004). An introduction to partial differential equations (2nd ed.). Springer.

Renardy, Michael, and Robert C. Rogers. An Introduction to Partial Differential Equations. 2nd ed. New York, NY: Springer, 2004.

Renardy, Michael, and Robert C. Rogers. An Introduction to Partial Differential Equations. 2nd ed. Springer, 2004.