R. äre, Wang, C., and Seavert, C.,
“A model of site-specific nutrient management”,
Applied Economics, vol. 44131, no. 33, pp. 4369 - 4380, 2012.
R. M. Cross and äre, R.,
“Farrell efficiency under value and quantity data”,
Journal of Productivity Analysis, vol. 29, no. 3, pp. 193 - 199, 2008.