TY - JOUR T1 - Ongoing build-up of refractory organic carbon in boreal soils during the Holocene JF - Science Y1 - 2006 A1 - Smittenberg, R. H. A1 - Eglinton, T. I. A1 - Schouten, S. A1 - Sinninghe-Damste, J. S. VL - 314 N1 - id: 1146 ER -