Fowler D, Dragosits U, Pitcairn CER, Sutton MA, Hall J, Roy DB, Weidemann A. Deposition of acidifying and eutrophying air pollutants in Scotland: Mapping critical loads, critical levels and exceedances. Centre for Ecology and Hydrology; 2001.

Hill MO, Mountford JO, Roy DB, Bunce RGH. Ellenberg's indicator values for British plants: ECOFACT volume 2 technical annex. HMSO; 1999.

Hill MO, Downing TE, Berry PM, Coppins BJ, Hammond PS, Marquiss M, Roy DB, Telfer MG, Welch D. Climate change and Scotland's Natural Heritage - An environmental audit. Battleby: Scottish Natural Heritage; 1998.