1. Liquid Level Detection in Cryogenic Environment;Chen,1999
2. Fiber optical liquid level sensor under cryogenic environment;Yang,2001
3. “Total Internal Reflection”, http://hyperphysics.phy-astr.gsu.edu/Hbase/phyopt/totint.html.
4. Liquid-level sensor with optical fibers
5. The Commercialization of fiber optic sensors;Crossley,2002