1. Granat L.: 1988, Influence from sampling site surrounding on amount and composition of collected precipitation samples. Proc. of Expert meeting on sampling, chemical analysis and quality assurance. Arona (Italy) 11 to 14 October 1988. EMEP-CCC-Report 4/88, 237?241
2. Granat L.: 1993, Long term changes in precipitation chemistry. Workshop on integrated monitoring of air pollution effects on ecosystems, ed Jiri Cerny. Prague, September 17?20 1993.
3. Graustein W. C. and Armstrong R. L.: 1983,Science 219, 289?292
4. Hedin L. O., Granat L., Likens G. E., Buishand T. A., Galloway J. N., Butler T. J. and Rodhe H.: 1994,Nature 367, 351?354
5. Hultberg H. and Ferm M.: 1995, Water Air and Soil Pollut. this volume.