Rychkov, V., Koukkari, P., Kirillov, S. and Kirillov, E. 2017. Best Practices of Russia and Finland in Extracting REE from Fertilizer Waste. KnE Materials Science. 2, 2 (Sep. 2017), 168-173. DOI:https://doi.org/10.18502/kms.v2i2.965.