References
https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve
http://science.nationalgeographic.com/science/space/universe/stars-article/
http://www.universetoday.com/13507/what-is-the-biggest-star-in-the-universe/
http://www.universetoday.com/19516/constellations/
http://www.space.com/57-stars-formation-classification-and-constellations.html
http://www.solarsystemquick.com/universe/ursa-major-constellation.htm
http://science.nationalgeographic.com/science/space/universe/stars-article/
http://www.universetoday.com/13507/what-is-the-biggest-star-in-the-universe/
http://www.universetoday.com/19516/constellations/
http://www.space.com/57-stars-formation-classification-and-constellations.html
http://www.solarsystemquick.com/universe/ursa-major-constellation.htm