@article{Carlsson_Carlsson_Wallin_Wallin_1991, place={Lund, Sweden}, title={Great Tits incubating empty nest cups}, volume={1}, url={https://journals.lub.lu.se/os/article/view/23096}, DOI={10.34080/os.v1.23096}, number={1}, journal={Ornis Svecica}, author={Carlsson, Hjordis and Carlsson, Leif and Wallin, Christina and Wallin, Nils-Erik}, year={1991}, month={Jan.}, pages={51–53} }