Evans, L.C. (2010) Partial differential equations. 2nd ed. Providence, R.I.: American Mathematical Society.
Farlow, S.J. (1993) Partial differential equations for scientists and engineers. New York: Dover Publications.
John, F. (1982) Partial differential equations. 4th ed. New York: Springer-Verlag.
Strauss, W.A. (2008) Partial differential equations: an introduction. 2nd ed. New York: Wiley.