Hanel, Andrea; Carlberg, Carsten (2020). „Skin Colour and Vitamin D: An update“. Experimental Dermatology. 29 (9). "Interestingly, eastern and Scandinavian hunter-gatherers had light skin,[48] in contrast to Baltic hunter-gatherers who kept their dark skin only until 3800 years ago when farming was introduced in this region by the Bronze Age expansion of people of Russian steppe origin.[56, 57]"