Birds -- Counting -- Congresses. : Estimating numbers of terrestrial birds : proceedings of an international symposium held at Asilomar, California, October 26-31, 1980 / editors, C. John Ralph and J. Michael Scott ; sponsors, California Natural Resources Federation ... [and others]
1981
1
6
Birds -- Counting -- Europe. : A best practice guide for wild bird monitoring schemes / editors, P. Voříšek ... [and others]