Pihu, T., Konist, A., Puura, E., Liira, M., Kirsimäe, K. Properties and environmental impact of oil shale ash landfills // Oil shale (2019) vol. 36, 2, p. 257–270 : ill. http://www.kirj.ee/public/oilshale_pdf/2019/issue_2/OS-2019-2-257-270.pdf https://doi.org/10.3176/oil.2019.2.01