Gerard Kuiper Biography Sources

https://solarsystem.nasa.gov/people/profile.cfm?Code=KuiperG

http://www.encyclopedia.com/topic/Gerard_Peter_Kuiper.aspx#3-1E1:KuiperGer-full

http://www.britannica.com/EBchecked/topic/324484/Gerard-Peter-Kuiper

http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/kuiper-gerard.pdf