Gagen, M., McCarroll, D., Robertson, I., Loader, N., & Jalkanen, R. (2008). Do tree ring δ13C series from Pinus sylvestris in northern Fennoscandia contain long-term non-climatic trends? Chemical Geology, 252(1-2), pp. 42-51. doi:10.1016/j.chemgeo.2008.01.013

Gagen, Mary, Danny McCarroll, Iain Robertson, Neil Loader, and Risto Jalkanen. "Do Tree Ring δ13C Series From Pinus Sylvestris in Northern Fennoscandia Contain Long-term Non-climatic Trends?" Chemical Geology 252, no. 1-2 (2008): 42-51.

Gagen, Mary, et al. "Do Tree Ring δ13C Series From Pinus Sylvestris in Northern Fennoscandia Contain Long-term Non-climatic Trends?" Chemical Geology 252.1-2 (2008): 42-51.