1. ARSI Project.
http://echord.eu/essential_grid/arsi-aerial-robot-for-sewer-inspection/index.html
2. BBC News.
https://www.bbc.com/news/uk-england-devon-46787461
3. Flyability platform.
https://www.flyability.com
4. SIAR Project.
https://siar.idmind.pt
5. The Guardian.
https://www.theguardian.com/environment/2017/sep/12/total-monster-concrete-fatberg-blocks-london-sewage-system