Routledge: Early childhood policies in low- and middle-income countries
Mindshift:
https://www.kqed.org/mindshift/49205/why-preschool-is-the-most-important-year-in-a-childs-development
NEA:
http://www.nea.org/home/18226.htm
Brookings Institute:
https://www.brookings.edu/opinions/does-pre-k-work-or-not/