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http://www.hse.gov.uk/pubns/books/hsg238.htm
. Accessed 17 August 2010
2. IEC (2000) IEC 61508 Functional safety of electrical/electronic/programmable electronic safety-related systems, Parts 1 to 7. International Electrotechnical Commission
3. IEC (2005) IEC 61508 Functional safety of electrical/electronic/programmable electronic safety-related systems, Part 0. International Electrotechnical Commission
4. IEC (2010a) IEC 61508 Functional safety of electrical/electronic/programmable electronic safety-related systems, Parts 1 to 7, Edition 2.0. International Electrotechnical Commission
5. IEC (2010b) IEC 61784-3 Industrial communication networks – profiles – Part 3: functional safety fieldbuses – general rules and profile definitions, Edition 2.0. International Electrotechnical Commission