Impact of high energy milled activation on the thermal properties of Bulgarian and Estonian natural apatitesPetkova, Vilma; Kostova, Bilyana; Serafimova, Ekaterina; Kaljuvee, Tiit; Tõnsuaadu, Kaia; Pelovski, Yoncho2nd Journal of Thermal Analysis and Calorimetry Conference, Budapest, June 18–21, 2019 : book of abstracts2019 / p. 480-481 https://jtac-jtacc.akcongress.com/ Phase and structural investigations of the content of natural radionuclides in rock and inorganic building materialsSerafimova, Ekaterina; Petkova, Vilma; Kaljuvee, TiitIOP conference series : materials science and engineering2023 / 8 p. : ill https://doi.org/10.1088/1757-899x/1264/1/012003 Thermochemical characterization of chicken litter and peat as a source for energy recoveryPetkova, Vilma; Serafimova, Ekaterina; Kaljuvee, Tiit; Pelovsky, YonchoJournal of thermal analysis and calorimetry2013 / p. 683-692 : ill