Quinn, J L, L Still, M C Carrier, J S Kirby, and P Lambdon. 1996. “Scaup Aythya Marila Numbers and the Cockle Cardium Edule Fishery on the Solway Firth: Are They Related?”. Wildfowl, January, 187-94. https://tidsskrift.dk/Wildfowl/article/view/154634.