1. Sustainability Goals of the United Nations. https://sdgs.un.org/goals
2. Volkswagen AG environmental compliance. https://www.volkswagenag.com/en/sustainability/environment/environmental-compliance.html
3. Volkswagen AG sustainability strategy. https://www.volkswagenag.com/en/sustainability/environment.html
4. Volkswagen AG sustainability mission. https://www.volkswagenag.com/presence/nachhaltigkeit/documents/Mission_Statement_Environment_2019-06-20_en_final_hoch.pdf
5. ISO 14001:2015. https://www.iso.org/iso-14001-environmental-management.html