REIJNDERS, P. J.; BRASSEUR, S. M.; TOUGAARD, S.; SEIBERT, U.; BORCHARDT, T.; STEDE, M. Population development and status of harbour seals (<i>Phoca vitulina</i&gt;) in the Wadden Sea. NAMMCO Scientific Publications, v. 8, p. 95-105, 1 Sep. 2010.