Krupa SV. Effects of atmospheric ammonia (NH3) on terrestrial vegetation: a review. Environmental Pollution. 2003  ;124:179-221.

Legge AH, Krupa SV. Effects of sulphur dioxide. In: Air Pollution and plant life. 2ndnd ed. Air Pollution and plant life. Chichester: John Wiley & Sons; 2002. pp. 135-162.