Hansen, J., L.H. Hansen, N.M. Schmidt and J. Reneerkens. Bird Monitoring at Zackenberg, Northeast Greenland, 2007.
Ziolkowski Jr., D.J., K.L. Pardieck and J.R. Sauer. The 2003-2008 Summary of the North American Breeding Bird Survey.
Lowe, J.D. (Ed.) Breeding Bird Census: 2007.
Lowe, J.D. (Ed.) Breeding Bird Census: 2008.
Baillie, S.R., J.H. Marchant, D.I. Leech, A.C. Joys, D.G. Noble, C. Barimore, I.S. Downie, M.J. Grantham, K. Risely and R.A. Robinson. Breeding Birds in the Wider Countryside: their conservation status 2009. Trends in numbers and breeding performance for UK birds. (2010) BTO Research Report No. 541. British Trust for Ornithology, Thetford.
Holt, C.A., G.E. Austin, N.A. Calbrade, H.J. Mellan, R.M. Thewlis, C. Hall, D.A. Stroud, S.R. Wotton and A.J. Musgrove. Waterbirds in the UK 2007-08: The Wetland Bird Survey. (2009) BTO/WWT/RSPB/JNCC, Thetford.