Campos, A. R., P. Catry, J. Ramos, and J. Robalo. 2011. “Competition Among European Robins Erithacus Rubecula in the Winter Quarters: Sex Is the Best Predictor of Priority of Access to Experimental Food Resources”. Ornis Fennica 88 (4):226–233. https://doi.org/10.51812/of.133786.