1. U.S. Environmental Protection Agency. http://www.epa.gov.
2. Major hazard pipelines: a comparative study of onshore transmission accidents;Papadakis;J Loss Prevent Process Ind,1999
3. Personal communication. Prof. Dr. Cláudio Ruggieri.
4. Cayard MS, Kane RD, Joia CJB, Correa LA. Hydrogen flux monitoring devices in wet H2S service. PTQ SUMMER; 1999. p. 71–7. http://www.eptq.com/Pages/Articles/Summer1999.htm.
5. Bruno TV, Craig BD, McHaney JH. Welding structure for sour service. http://www.metallurgical.com/Publications/Publication%2020.pdf).