Breeze T.D., Bailey A.P., Balcombe K.G. and Potts S.G. (2014) Costing conservation: an expert appraisal of the pollinator habitat benefits of England's Entry Level StewardshipBiodiversity and Conservation 23 (5): 1193-1214. http://link.springer.com/article/10.1007%2Fs10531-014-0660-3