Sheppard LJ, Crossley A, Harvey F, Parrington J, White CC. Early effects of acid mist on Sitka spruce planted on acid peat. Phyton (Horn Austria). 1998  ;39:1-25.

Crossley A, Sheppard LJ, Cape JN, Smith RI, Harvey F. Stem growth reductions in mature Sitka spruce trees exposed to acid mist. Environmental Pollution. 1997  ;96:185-193.