Application of carbon isotopes to the study of the Ordovician and Silurian of the BalticMartma, Tõnu2006 https://digi.lib.ttu.ee/i/?107 https://www.ester.ee/record=b2209327*est Eesti vete isotoopkoostisVaikmäe, ReinEesti Geograafia Seltsi aastaraamat = Yearbook of the Estonian Geographical Society. 47. kd2024 / lk. 36-46 https://www.ester.ee/record=b1237665*est Isotoop-paleoklimatoloogia ja -hüdroloogiaVaikmäe, ReinGeoloogia instituudi kuuskümmend viis aastat : loomine ja muutumised, inimesed ja teadus, meenutused ja suundumused2012 / lk. 138-143 : fot Searching for the Ordovician-Silurian boundary in Estonia, Latvia and LithuaniaMeidla, Tõnu; Hints, Olle; Ainsaar, LehoEstonian journal of earth sciences2023 / p. 70-73 : ill https://doi.org/10.3176/earth.2023.53 Variations in carbon isotope composition of microfossils and bulk organic matter from the Middle Ordovician through Wenlock (Silurian) in EstoniaHints, Olle; Kaljo, Dimitri; Kaptein, Helja; Martma, Tõnu; Munnecke, Axel10th Baltic Stratigraphic Conference : Checiny, 12-14 September 2017 : abstracts and field guide2017 / p. 36-37 http://geo.uw.edu.pl/tl_files/publikacje/10th_Baltic_Stratigraphic_Conference_Abstracts_and_Field_Guide.pdf