1. Resilience and Stability of Ecological Systems
2. BBC Newshttps://www.bbc.co.uk/news/uk-scotland-13868638
3. Cleopatra’s Needle: The story behind the obeliskshttps://www.ancient-origins.net/artifacts-other-artifacts/cleopatra-s-needle-story-behind-obelisks-007051
4. Increasing the durability of building constructions;Lstiburek;Build. Sci. Dig.,2006
5. Principles of Economics;Menger,1871