1. Kaar, E. 1990. Green areas for the ashfields of oil shale industry. Production and Environment. (In Estonian), Tallinn, Kohtla-Järve, pp. 33–36
2. Liblik, V., Rätsep, A., 1994. Pollution sources and distribution of pollutants. In: Punning, J.-M. (Ed.), The Influence of Natural and Anthropogenic Factors in the Development of Landscapes. The Results of a Comprehensive Study in NE Estonia. Publication 2/1994, Institute of Ecology, Estonian Academy of Sciences. Tallinn, Estonia, pp. 70–93
3. Puura, I., Bauret, H., Roose, A., 1991. Oil shale geology and mining. European Workshop on Human Impact on Environment. Excursion Routes. Tartu-Tallinn-Uusküla, pp. 43–53
4. Reinsalu, E., Toomik, A., Kaljuvee, E., 1992. Ecological problems associated with oil shale mining. The Environmentally Sound Management of Low-grade Fuels. Proc. in Sem. Stockholm Environment Institute, Stockholm, Sweden, pp. 157–164
5. Toomik, A., Kaljuvee, E., 1994. Changes in the landscape caused by oil shale mining. In: Punning, J.-M. (Ed.) The Influence of Natural and Anthropogenic Factors in the Development of Landscapes. The Results of a Comprehensive Study in NE Estonia. Publication 2/1994, Institute of Ecology, Estonian Academy of Sciences. Tallinn, Estonia, pp. 150–160