1. Aune, L. & Gullvåg, B.M. (1991). The effect of different air pollution environmental exposures on the stomatal epicuticular wax layer of Picea and Pinus needles. Conference on Effects of Atmospheric Pollutants on Climate and Vegetation. Taormina, Sept. 26–29, 1991
2. Cape, J. N. (1986): Effects of air pollution on the chemistry of surface waxes of Scots pine. Water, Air, Soil Pollut.31, 393–399
3. Eriksson, G., Jensen, S., Kylin, H. &Strachan, W. (1989): The pine needle as a monitor of atmospheric pollution. Nature341, 42–44
4. Elteneuer-Macher, T. (1990): Morphologie und Chemie der Epicuticular-Wachse vonPicea abies (L.) Karsten unter dem Einfluß von Klima und Immissionen. Gebrüder Borntraeger Verlagsbuchhandlung, Berlin, Stuttgart
5. Frank, H. (1991): Airborne Chlorocarbons, Photooxidants, and Forest Decline. Ambio20, 13–18