Nguyen Thi, H.T., Vu, H., Ha, L.A., Trinh, V.G. and Nguyen, V.V. 2018. A procedure of determining carbon-13 composition in soil organic carbon on an Isotope Ratio Mass-Spectrometer. Nuclear Science and Technology. 8, 1 (Mar. 2018), 23-28. DOI:https://doi.org/10.53747/jnst.v8i1.80.