Here I list some important sources that have helped me to better understand computational quantum chemistry. The sources are rather disorganised; perhaps I will try to organize them in the future.

• Lots of excellent resources from The Sherrill Research Group 

• Prof. Chris Cremer's lectures on Computational Chemistry (highly recommended) 

• Book: Essentials of Computational Chemistry: Theories and Models by  Christopher J. Cramer

• Teaching the Theory in Density Functional Theory Video Series by CECAM