1. The Virgo Collaboration, “Advanced Virgo technical design report,” Virgo internal document VIR-0128A-12 (2012) https://tds.ego-gw.it/itf/tds/index.php?callContent=2&callCode=9317.
2. Multiple-surface phase-shifting interferometry
3. http://www.zygo.com/?/met/profilers/newview7000 [June 2014]
4. https://www.qedmrf.com/mr-fluids [June 2014]
5. Test optics error removal