2. e-PG Pathshala – https://epgp.inflibnet.ac.in/
3. National Science Digital Library – http://nsdl.niscair.res.in/jspui/
4. Vidya Mitra- https://vidyamitra.inflibnet.ac.in/
5. Free online encyclopaedia – https://www.encyclopedia.com/
6. National Knowledge Network – http://nkn.gov.in/en/
7. National Digital Library of India – https://ndl.iitkgp.ac.in/
8. ShodhGanga- https://shodhganga.inflibnet.ac.in:8443/jspui/
9. PDF Drive- https://www.pdfdrive.com/
10. Internet arichive – https://archive.org/