• Comparative study of antioxidant capacity of Rheum rhaponticum root polyphenolsRaudsepp, Piret; Helmja, Kati; Raal, Ain; Vaher, Merike; Püssa, TõnuXXIVth International Conference on Polyphenols : Polyphenols Communications 2008 : Salamanca, 8th-11th July 2008. Volume 12008 / p. 231-232 : ill https://www.researchgate.net/publication/286933217_Comparative_study_of_antioxidant_capacity_of_Rheum_rhaponticum_root_polyphenols
• The evaluation of the oxidation capability of bioactive compounds of Solanum melongena by capillary electrophoresis and by HPLC-MS/MSHelmja, Kati; Vaher, Merike; Püssa, Tõnu; Kaljurand, MihkelXXIVth International Conference on Polyphenols : Polyphenols Communications 2008 : Salamanca, 8th-11th July 2008. Volume 12008 / p. 165-166 : ill