[1] Gruychev G. 2021 Breeding birds in Northwestern Sakar Mountain, Bulgaria. Forestry Ideas 27 (1): 119–127.

[2] Benaradj A., Charchar N., Boucherit H., Ouakid M.-L., Houhamdi M. 2022 Phenology and diurnal behaviour of ruddy shelduck Tadorna ferruginea at Oglat Eddaira (Ain Ben Khlil) wetland, Southwest of Algeria. Ekológia (Bratislava) 41 (1): 70–77. https://doi.org/10.2478/eko-2022-0008