1. Sight Flow Indicators Handbook. L.J. Star Inc. Published 2012. Accessed January 5 2022.https://www.ljstar.com/wp-content/uploads/2020/01/sight-flow-indicators-handbook.pdf
2. Chemical and Pharmaceutical Sight Glass Application Handbook. L.J. Star Inc. Published 2007. Accessed January 5 2022.https://www.ljstar.com/wp-content/uploads/2019/11/chemical-pharmaceutical-handbook.pdf
3. Understanding the Difference between Annealed Glass and Tempered Glass. Swift Glass Company. Accessed January 7 2022.https://info.swiftglass.com/lp-understanding-difference-between-annealed-glass-and-tempered-glass.
4. Fuseview ANSI/DIN Sight Glass. JM Canty Inc.https://www.jmcanty.com/product/ansi-din-fuseview-sight-glass/. Accessed January 7 2022.