Singh, Aradhana (Lead Author); Lakhdar Boukerrou and Michelle Miller (Topic Editors). Diversification in agricultureArchivado el 21 de junio de 2010 en Wayback Machine.. In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). (Published in the Encyclopedia of Earth November 17, 2009; Retrieved February 22, 2010).
Singh, Aradhana (Lead Author); Lakhdar Boukerrou and Michelle Miller (Topic Editors). Diversification in agricultureArchivado el 21 de junio de 2010 en Wayback Machine.. In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). (Published in the Encyclopedia of Earth November 17, 2009; Retrieved February 22, 2010).