14Rynne, Etenne. "Two Stone Axeheads Found near Beltany Stone Circle, Co. Donegal." Journal of the Royal Society of Antiquaries of Ireland 93.2 (1963): 193-96.
According to Rynne, while it is not possible to definitively connect the axeheads with the stone circle, they do provide evidence of trading contacts in Ireland 4000 years ago.