References
- Ormrod , D. P. , Proctor , J. T. A. , Hofstra , G. and Phillips , M. L. 1980 . Air pollution effects on agricultural crops in Ontario: A review . Can. J. Plant Sci. , 60 : 1023 – 1030 .
- Ormrod , D. P. 1978 . Pollution in horticulture , Amsterdam : Elsevier .