Zhou, Y., Jiang, X., Schaub, M., Wang, X., Han, J., Han, Sjie, & Li, M. H. (2013). Ten-year exposure to elevated CO2 increases stomatal number of Pinus koraiensis and P. sylvestriformis needles. European Journal of Forest Research, 132(5-6), 899-908. https://doi.org/10.1007/s10342-013-0728-8