http://en.wikipedia.org/wiki/Partial_differential_equation

http://www.math.hmc.edu/~ajb/PCMI/lecture1.pdf

http://eqworld.ipmnet.ru/en/solutions/fpde/fpdetoc1.pdf

http://reference.wolfram.com/mathematica/tutorial/DSolveLinearAndQuasiLinearFirstOrderPDEs.html

http://www.math.mcgill.ca/labute/courses/319b.01/linear1.pdf

http://www.math.nyu.edu/faculty/varadhan/pdefin/section2.pdf

http://www.ma.utexas.edu/users/davis/375/LECTURES/L11/cauchy.pdf

http://www.civil.uwaterloo.ca/cive331/images/chapter%201.pdf

http://ocw.mit.edu/courses/mathematics/18-305-advanced-analytic-methods-in-science-and-engineering-fall-2004/lecture-notes/third1.pdf

http://school.maths.uwa.edu.au/~keady/Teaching/EnvironmentalEng/ENVE3605/Lectures/envePDE1.pdf

http://www.utdallas.edu/~cantrell/ee6481/lectures/pde.pdf

http://www.maths.tcd.ie/~pete/pde/2009sol.pdf

http://www.iitk.ac.in/math/faculty/malayb/pdenotes.pdf

http://www.iitk.ac.in/math/faculty/malayb/pdenotes.pdf

http://elearning.vtu.ac.in/Programme%2016/ENotes/Maths2/Unit4-VL.pdf

http://www.math.nps.navy.mil/~bneta/pde.pdf

http://www.nd.edu/~atassi/Teaching/ame60612/Notes/pde.pdf

http://banach.millersville.edu/~bob/math467/Review/main.pdf

http://math.berkeley.edu/courses/archives/exams