1. Layer of Protection Analysis: Simplified Process Risk;Bai,2011
2. Layers of protection analysis for human factors;Baybutt;Process Saf. Prog.,2002
3. CCPS, 2001. Layer of Protection Analysis: Simplified Risk Assessment.
4. LOPA as practiced at a global manufacturing API facility;Evenson;Process Saf. Prog.,2009
5. IEC, 2010. Functional safety of electrical/electronic/programmable electronic safety-related systems-Part 4: definitions and abbreviations.