* [http://en.wikipedia.org/wiki/Natural_capital הון טבעי] בוויקיפדיה האנגלית
* [http://en.wikipedia.org/wiki/Natural_capital הון טבעי] בוויקיפדיה האנגלית
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Mathis Wackernagel, William E. Rees [http://www.sciencedirect.com/science/article/pii/S0921800996000778 Perceptual and structural barriers to investing in natural capital: Economics from an ecological footprint perspective], Ecological Economics, Volume 20, Issue 1, January 1997, Pages 3-24