WHO.
Air Quality Guidelines for Europe. . Copenhagen: World Health Organisation; 2000.
Organization WH.
Air quality guidelines for Europe. Copenhagen: World Health Organization; 1987.
EPA US.
Ambient Water Quality Criteria for copper. Washington, DC: Environmental Protection Agency; 1984.
Mulgrew A, Williams P.
Biomonitoring of air quality using plants. Berlin, Germany: WHO Collaborating Centre for Air Quality Management and Air Pollution Control; 2000.