Pilegaard, K., Ibrom, A., Courtney, M. S., Hummelshøj, P., & Jensen, N. O. (2011). Increasing net CO2 uptake by a Danish beech forest during the period from 1996 to 2009. Agricultural and Forest Meteorology, 151, 934-946. doi:10.1016/j.agrformet.2011.02.013.