OSHA TECHNICAL MANUAL – SECTION IV: CHAPTER 4 https://www.osha.gov/dts/osta/otm/otm_iv/otm_iv_4.html ↩
http://www.ssl.umd.edu/projects/rangertsx/data/spacerobotics-UNDSPST470.pdf Archived 2017-11-16 at the Wayback Machine , pg 9 http://www.ssl.umd.edu/projects/rangertsx/data/spacerobotics-UNDSPST470.pdf ↩