Moroń D., Grześ I., Skórka P., Szentgyörgyi H., Laskowski R., Potts S.G., Settele J., Woyciechowski M (2012) Abundance and diversity of wild bees along gradients of heavy metal pollutionJournal of Applied Ecology 49 (1): 118–125. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2011.02079.x/abstract