Report on the 1995 Survey of the Freshwater Pearl Mussel (Margaritifera L., 1758) : Rivers Torridge, Clun, Esk, Irt, Ehen, Rede & N. Tyne /
Oliver, P. Graham.
Killeen, Ian J.
English Nature (Agency)
[London] : English Nature,
1996.
Contract no. D75-08-68.
Includes bibliographical references.