| Title | Authors | Year | 
|---|---|---|
| Physiological-effects of long-term exposure to low concentrations of SO2 and NH3 on poplar leaves | 
                               Hove, L.W.A…  | 
                                                                                        1991 | 
| The yield of winter cereals exposed to sulphur dioxide under field conditions. | 
                               McLeod, A.R…  | 
                                                                                        1991 | 
| Acid deposition: its nature and impacts | 
                               Last, F.T…  | 
                                                                                        1991 | 
| Acidic deposition: its nature and impacts | 
                               Last, F.T…  | 
                                                                                        1991 | 
| Nitrate in soil water | 
                               Westling, O…  | 
                                                                                        1991 | 
| Effects of sulphur dioxide on the development of fungal diseases of winter barley in an open-air fumigation system. | 
                               Mansfield,…  | 
                                                                                        1991 | 
| Acid Rain - Critical and Target Load Maps for the United Kingdom | 
                               Environment…  | 
                                                                                        1991 | 
| Environmental Health Criteria 125 Platinum | 
                               WHO,  | 
                                                                                        1991 | 
| Zeigerwerte von Pflanzen in Mitteleuropa | 
                               Ellenberg,…  | 
                                                                                        1991 | 
| Nitrogen Uptake and Allocation by Calluna-Vulgaris (L) Hull and Deschampsia-Flexuosa (L) Trin Exposed to 15NH3 | 
                               Dueck, T.A…  | 
                                                                                        1991 |