Lupak, Oksana, Halyna Kovalchuk, and Halyna Antonyak. 2017. “Potentiometric Determination of Antioxidant Activity of Extracts of Calendula Officinalis L. Plants under the Influence of Growth Biostimulants”. ScienceRise: Biological Science, no. 6 (9) (December):10-13. https://doi.org/10.15587/2519-8025.2017.119086.