Further reading
Obituary: Density Functional Theory (1927-1993)
What functional should I choose
DFT in a nutshell (open-access article)
Density-Functional approximations for exchange and correlation by Viktor N. Staroverov
Some Fundamental Issues in Ground-State Density Functional Theory: A Guide for the Perplexed
Fifty years of density-functional theory in chemical physics - Axel Becke perspective