* [[http://www.cnczone.com/forums/diy-cnc-router-table-machines/140804-proper-axis-orientation-cnc-routers.html#post1023027]]
  * [[https://www.linkedin.com/pulse/coordinate-system-axis-naming-conventions-cameron-anderson]]
  * [[http://multicam.ca/how-cnc-routers-work-and-the-difference-between-3-axis-and-5-axis-machines/]]