1. https://www.nrep.org/blog/environmental-audit
2. https://sitemate.com/uk/resources/articles/environmental/environmental-auditing-process/
3. https://www.envass.co.za/environmental-audit-types-and-benefits/
4. https://www.routledge.com/Environmental-Performance-Auditing-in-the-Public-Sector-Enabling-Sustainable/Prasad/p/book/9780367856045
5. https://static1.squarespace.com/static/57019a6db6aa607cbb909ab2/t/5923b3d12e69cf8a531eded1/1495512024499/ISSAI+5120+E+Endorsement+version_2016.pdf