http://space-facts.com/the-sun/

http://www.universetoday.com/16338/the-sun/

https://solarsystem.nasa.gov/planets/profile.cfm?Object=Sun&Display=OverviewLong

http://hea-www.harvard.edu/scied/SUN/sunpage.html

http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sun

References