A sample survey of the flora of Britain and Ireland : the Botanical Society of the British Isles monitoring scheme 1987-1988 /
Palmer, Margaret,1935-
Bratton, J. H.
Joint Nature Conservation Committee (Great Britain)
Peterborough : Joint Nature Conservation Committee,
1995.
"Based on a report for the Nature Conservancy Council by T.C.G. Rich and E.R. Woodruff."