Bräger, I. S.; Meissner, J.; Thiel, M. Temporal and Spatial Abundance of Wintering Common Eider Somateria Mollissima, Long Tailed Duck Clangula Hyemalis, and Common Scoter Melanitta Nigra in Shallow Water Areas of Southwestern Baltic Sea. Ornis Fenn 1995, 72, 19–28.