1. Almborn, O. (1948) Distribution and ecology of some South Scandinavian lichens, Botaniska Notiser Supplement 1, 1–254.
2. Ammann, K., Herzig, R., Liebendoerfer, L., and Urech, M. (1987) Multivariate correlation of deposition data of 8 different air pollutants to lichen data in a small town in Switzerland, in Advances in Aerobiology, Birkhäuser Verlag, Basel, pp. 401–406.
3. Aptroot, A. and Van den Boom, P.P.G. (1998) Pyrenocollema chlorococcum a new species with a chlorococcoid photobiont from zinc-contaminated soils and wood, Cryptogamie Bryologie Lichénologie 19, 193–196.
4. Asman, W.A.H. and Van Jaarsveld, J.A. (1990) A variable resolution statistical transport model applied for ammonia and ammonium, Rijksinstituut voor Volksgezondheid en Milieu, Bilthoven, RIVM report 228471007.
5. Baddeley, M.S., Ferry, B.W., and Finegam, E.J. (1973) Sulphur dioxide and respiration in lichens, in B.W. Ferry, M.S. Baddeley, and D.L. Hawksworth (eds.), Air Pollution and Lichens, The Athlone Press of the University of London, London, pp. 299–313.