Kleijn, D., Rundlöf, M., Scheper, J., Smith, H.G., Tscharntke, T. (2011) Does conservation on farmland contribute to halting the biodiversity decline?Trends in Ecology & Evolution 26 (9): 474-481. http://www.cell.com/trends/ecology-evolution/abstract/S0169-5347(11)00142-X