PROJECT GUTENBERG https://www.gutenberg.org/ebooks/
SHODHGANGOTRI https://shodhgangotri.inflibnet.ac.in/
DOAJ https://doaj.org/
EGYANKOSH https://egyankosh.ac.in/
GOOGLE SCHOLAR https://scholar.google.com/
SHODHGANGA https://shodhganga.inflibnet.ac.in/
E SHODHSINDHU https://ess.inflibnet.ac.in/
ERIC https://eric.ed.gov/