1 | The water quality of the Humber Estuary 1992 : a report from The Humber Estuary Committee |
2 | State of the environment report 2001 : West Midlands Region |
3 | Second annual review of the Lower Bristol Avon catchment management plan |
4 | National marine baseline survey 1995 : littoral cell 11 : Great Orme to the Solway Firth |