Mwebaze, P., Marris, G. C., Budge, G. E., Brown , M., Potts, S. G., Breeze, T. D. and Macleod, A. (2010) Quantifying the value of ecosystem services: a case study of honeybee pollination in the UK. In: 12th Annual BIOECON Conference 'From the Wealth of Nations to the Wealth of Nature: Rethinking Economic Growth' , 27-28 September 2010, Venice, Italy.
Nick Hanley, Tom D. Breeze, Ciaran Ellis, David Goulson.,Measuring the economic value of pollination services: Principles, evidence and knowledge gaps. Ecosystem Services Available online 22 October 2014
See also Melathopoulos et al. 2015 that just got published in Ecological Economics...a very comprehensive review and critique of pollination valuation...