A winter bird audit for the Colworth Estate, 1999/2000, 2000/2001 /
Henderson, I. G.
Clark, N. A.(Nigel A.)
Gough, S.
British Trust for Ornithology.
Norfolk : British Trust for Ornithology,
c2012.
'October 2001' - t.p.
Bibliography: p. 17.
Water birds