296,036 AIR Air quality in selected urban areas 1979-1980 : /GEMS : Global Environmental Minitoring System / prep, in cooperation with the WHO Collaborating Centre on Environmental Pollution Control, United States Environmental Protection Agency, Washington, DC, USA. — Geneva : World Health Organization, 1983. - 57 s. : il.; 30 cm (WHO Offset Publ.; nr 76) ISBN 92 4 1700769