Vilhelmsdotter Allander S., Marké L.- Åke, Wihlen B., Svensson M., Elinder C.-G., and Larsson A. “Regional Variation in Use of Exogenous and Endogenous Glomerular Filtration Rate (GFR) Markers in Sweden”. Upsala Journal of Medical Sciences, vol. 117, no. 3, Mar. 2012, doi:10.3109/03009734.2012.664179.