Quay, P., Sonnerup, R., Westby, T., Stutsman, J., & McNichol, A. (2003). Changes in the13C/12C of dissolved inorganic carbon in the ocean as a tracer of anthropogenic CO2uptake. Global Biogeochemical Cycles, 17(1), 4–1–4–20. doi:10.1029/2001gb001817