1. Astrain C, Zaragueta E (2006) Indirect assessment of an agri-environmental scheme aimed at the conservation of steppe birds in northern Spain. Ardeola 53:143–153
2. Berger G, Kaechele H, Pfeffer H (2006) The greening of the European common agricultural policy by linking the European-wide obligation of set-aside with voluntary agri-environmental measures on a regional scale. Environmental Science & Policy 9:509–524
3. Bockstaller C, Guichard L, Makowski D, Aveline A, Girardin P, Plantureux S (2008) Agri-environmental indicators to assess cropping and farming systems. A review. Agronomy for Sustainable Development 28:139–149
4. Bureau JC, Witzke HP, Berkhout P, Gohin A, Heckelei T, Kreyzer MA, Kleinhanss W, Matthews A, Merbis MD, Rudloff B, Salvatici L (2007) Reflection on the possibilities for the future development of the CAP. European Parliament, 2007, European Commission, Policy Department Structural and Cohesion Policies, Brussels, pp 1–74. www.europarl.europa.eu/activities/expert/eStudies.do?language=EN
5. Canton J, De Cara S, Jayet PA (2009) Agri-environmental schemes: Adverse selection, information structure and delegation. Ecological Economics 68:2114–2121