Nosova, M., E. Severova, and O. Volkova. “Spruce and Broadleaved Trees Pollen Percentages and PAR Values in the European Part of Russia: 9 Years of Pollen Trap Monitoring Implemented to the Fossil Data”. Ecological Questions, vol. 26, Aug. 2017, pp. 9-13, doi:10.12775/EQ.2017.009.