TTÜ võistkonna Feel Alive! liikmeid hämmastas tohutu toetusKaptein, HeljaMeie Maa2016 / lk. 4-5

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