Wang, L., Ibrom, A., Korhonen, J. F. J., Frumau, K. F. A., Wu, J., Pihlatie, M., et al. (2013). Interactions between leaf nitrogen status and longevity in relation to N cycling in three contrasting European forest canopies. Biogeosciences, 10(2), 999-1011. doi:10.5194/bg-10-999-2013.