1. Barthel M, Fava J, Harnanan C, Valdivia S, Khan S, James K, Smerek A (2014) Hotspots Analysis: mapping of existing methodologies, tools and guidance and initial recommendations for the development of global guidance. UNEP/SETAC Life Cycle Initiative-Flagship Project 3a (Phase 1) v.5.2. UNEP/SETAC Life Cycle Initiative website.
http://lifecycleinitiative.org/wp-content/uploads/2014/10/Flagship3a-Hotspots-Mapping.pdf
2. ISO 14040 (2006) Environmental management – life cycle assessment – principles and framework. A copy of this standard can be purchased.
http://www.iso.org/iso/catalogue_detail?csnumber=37456
3. UNEP/SETAC Life Cycle Initiative (2011) Towards a life cycle sustainability assessment: making informed choices on products. United Nations Environment Programme website.
http://www.unep.org/pdf/UNEP_LifecycleInit_Dec_FINAL.pdf