1. Lichens of the boreal coniferous zone;Ahti,1977
2. Fluoreszenzmikroskopischer Nachweis von Immissionsschäden an Flechten;Arnold;Angew. Bot.,1976
3. Field and laboratory studies on detergent damage to lichens at the Lizard, Corn· wall;Brown;Cornish Stud.,1974
4. Epiphytic lichens and air pollution in the Netherlands;De Wit;Bibliotheca Lichenologica,1976
5. The influence of an iron and steel works on the air of the surrounding area;Estlander;Study rapport (In Finnish) for the Institute of Occupational Health,1971