Citation
Gregory, R.D., Vorisek, P., Noble, D.G., Van Strien, A., Klvanova, A., Eaton, M., Meyling, A.W.G., Joys, A., Foppen, R.P.B. & Burfield, I.J. 2008. The generation and use of bird population indicators in Europe. Bird Conservation International 18: 244. doi:10.1017/S0959270908000312