ÅSTRÖM, M., and B. SPIRO. 2005. “Sources of Acidity and Metals in a Stream Draining Acid Sulphate Soil, till and Peat, Western Finland, Revealed by a Hydrochemical and Sulphur Isotope Study”. Agricultural and Food Science 14 (1):34-43. https://doi.org/10.2137/1459606054224084.