Differential Equations - Partial Differential Equations

http://tutorial.math.lamar.edu/Classes/DE/IntroPDE.aspx

http://fab.cba.mit.edu/classes/864.17/text/pde.pdf

http://issc.uj.ac.za/downloads/problems/partial.pdf

http://math.etsu.edu/multicalc/prealpha/chap2/chap2-4/printversion.pdf

https://ask.fxplus.ac.uk/tools/HELM/pages/workbooks_1_50_jan2008/Workbook25/25_1_partial_diffrntl_equatns.pdf

https://web.math.princeton.edu/~seri/homepage/papers/gws-2006-3.pdf

https://www.astro.umd.edu/~ricotti/NEWWEB/teaching/ASTR415/pres22.pdf

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

https://www.math.psu.edu/tseng/class/Math251/Notes-PDE%20pt1.pdf

https://www.math.ucla.edu/~yanovsky/handbooks/PDEs.pdf

https://www.math.uni-leipzig.de/~miersemann/pdebook.pdf

https://www.math.ust.hk/~machas/differential-equations.pdf

https://www.uni-muenster.de/Physik.TP/archive/typo3/fileadmin/lehre/NumMethoden/WS1011/script1011PDE.pdf

http://web.math.ucsb.edu/~grigoryan/124A.pdf

http://www1.maths.leeds.ac.uk/~kersale/Teach/M3414/Notes/m3414_1.pdf

http://www.csc.kth.se/utbildning/kth/kurser/DN1213/numme06/utdelat/kap10.pdf

http://www.it.uu.se/edu/course/homepage/finmet2/vt14/material/Lab3.pdf

http://www.math.chalmers.se/Math/Grundutb/CTH/mve030/1617/mve290-PDEs.pdf

http://www.maths.manchester.ac.uk/~kd/homepage/pdelec.pdf

http://www.math.stonybrook.edu/~mmovshev/mat341-fall18/Partial_Differential_Equations.pdf

http://www.physics.miami.edu/~nearing/mathmethods/pde.pdf

http://www.robots.ox.ac.uk/~jmb/lectures/pdelecture1.pdf