Qualitative and Quantitative Determination of Organic Acids in Crude Herbal Drugs and Medicinal Herbal Preparations for Quality Control in Russian Federation by Modern Physicochemical Methods, Sergunova, Ekaterina Vyacheslav, Sorokina Alla Anatolyevn, Bokov Dmitry Olegovich, and Marakhova Anna Igorevna , Pharmacognosy Journal, September 2019, Volume 11, Issue 5, p.1132-1137, (2019)