These standards are crucial in calculating the carbon footprint, because they give confidence in the credibility and transparency of carbon neutrality claims. Next to PEF and OEF, the most reliable and widely-used standards are ISO 14064, BSI: PAS 2050, GHG Protocol and Bilan Carbone®. In April 2013, the European Commission launched the Product Environmental Footprint (PEF) and the Organisation Environmental Footprint (OEF) in an attempt to harmonise the currently available carbon footprint standards.