United Nations Treaties and Principles on Outer Space
http://www.unoosa.org/pdf/publications/STSPACE11E.pdf
The Space Treaty: A Preliminary Evaluation
https://scholarship.law.berkeley.edu/cgi/viewcontent.cgi?article=2878&context=californialawreview
The Legal Status of Outer Space and Relevant Issues
https://www.law.upenn.edu/live/files/7834-chengdftissspclawjrnlspclawpdf
