1. A. L. Budantsev and E. E. Lesiovskaya, Wild Useful Plants of Russia [in Russian], Izd. CPKhFA, St. Petersburg (2001).
2. Methodical Instructions for Atomic Absorption Methods for Determining Toxic Elements in Food Products and Food Raw Material [in Russian], State Committee Sanepidnadzor, Moscow (1992).
3. USSR State Pharmacopeia, XI Ed., No. 2, Meditsina, Moscow (1990).