ON LINE ENCYCLOPEDIA

https://www.britannica.com

https://eol.org/

http://www.computerlanguage.com

http://www.eol.org

http://www.symbols.com/

http://www.nlm.nih.gov/medlineplus/encyclopedia.html

http://www.reference.com/

http://en.wikipedia.org/

http://wdl.org/en/

http://www.encyclopedia.com

https://en.m.wikipedia.org/wiki/Online_encyclopedia

https://www.britannica.com/topic/Encarta

https://en.m.wikipedia.org/wiki/Everything2

https://en.m.wikipedia.org/wiki/World_Book_Encyclopedia

https://en.m.wikipedia.org/wiki/Scholarpedia

http://www.daviddarling.info/encyclopedia/ETEmain.html

http://www.sf-encyclopedia.com

https://www.encyclopediaofmath.org/index.php/Main_Page.

https://en.m.wikipedia.org/wiki/Mathematics

https://www.britannica.com/topic/sports

http://eol.org

http://a-z-animals.com

https://www.britannica.com/science/ocean

http://www.oxfordreference.com

http://socialwork.oxfordre.com