http://hubblesite.org/reference_desk/faq/answer.php.id=63&cat=exotic

http://www.universetoday.com/23152/the-milky-ways-black-hole/

http://www.famousscientists.org/pierre-simon-laplace/

http://hubblesite.org/explore_astronomy/black_holes/encyc_mod1_observatories.html

https://www.e-education.psu.edu/astro801/content/l8_p7.html

http://www.deepastronomy.com/how-do-we-know-black-holes-exist.html

http://essayweb.net/astronomy/images/black_hole_large.jpg

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/010912a.html

http://www.britannica.com/EBchecked/topic/197134/event-horizon

http://www.maths.tcd.ie/pub/HistMath/People/Laplace/RouseBall/RB_Laplace.html

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971111e.html

http://www-math.ucdenver.edu/~wcherowi/courses/m4010/s08/mmlaplace.pdf

http://www.dailymail.co.uk/sciencetech/article-2285483/The-supermassive-black-hole-spinning-speed-light--holds-galaxys-history.html

http://astronomy.swin.edu.au/cosmos/S/Schwarzschild+Radius

References/Sources/Work Cited