1. Ahearn, A. (2008). Carbon-offset cowboys let their grass grow. Scientific American, Earth 3.0 Special edition December 2008. Retrieved 20 June 2008 from http://www.scientificamerican.com/article.cfm?id=carbon-cowboys .
2. Ayyad, M. A. (1981). Soil–vegetation–atmosphere interactions. In D. W. Goodall & R. A. Perry (Eds.), Arid land ecosystems (Vol. 2, pp. 9–49). Cambridge: Cambridge University Press.
3. Balazy, S. (2002). Ecological guidelines for the management of afforestations in rural areas. In L. Ryszkowski (Ed.), Landscape ecology in agroecosystems management (pp. 299–316). Boca Raton: CRC.
4. Callaway, R. M. (1998). Competition and facilitation on elevation gradients in sub-alpine forests of the northern Rocky mountains. USA Oikos, 82, 561–573.
5. Canadell, J., Jackson, R. B., Ehleringer, J. R., Mooney, H. A., Sala, O. E., & Schulze, E. D. (1996). Maximum rooting depth of vegetation types at the global scale. Oecologia, 108, 583–595.