References
Jimenez, R., Thejll, P., Jørgensen, U. G., MacDonald, J., & Pagel, B. (1996). Ages of globular clusters: a new approach. Retrieved from https://www.pnas.org/content/95/1/13.
Kirby, E. (2018).  Ay101 MESA Project. (pdf). Retrieved from http://www.astro.caltech.edu/~enk/Ay101/pages/Ay101_MESA_Project.pdf
Palma, C. 2018.  ASTRO 801: Measuring the Age of a Star Cluster. (Class website). Retrieved from https://www.e-education.psu.edu/astro801/content/l7_p6.html.