@article{Karlsson_2005, place={Lund, Sweden}, title={Egg size in Black-headed Gulls Larus ridibundus}, volume={15}, url={https://journals.lub.lu.se/os/article/view/22756}, DOI={10.34080/os.v15.22756}, number={1}, journal={Ornis Svecica}, author={Karlsson, Thomas}, year={2005}, month={Jan.}, pages={46–47} }