Sawicki, J., Szczecińska, M., Korniak, T., & Hołdyński, C. (2006). Genetic variation within and between an isolated population of Phyteuma spicatum L. ssp. coeruleum R. Schulz near Mrągowo (northeastern Poland) and populations of P. spicatum L. ssp. spicatum. Biodiversity: Research and Conservation, (1-2), 50–53. https://doi.org/10.14746/biorc.2006.1-2.11