Callander, J Graham. “Long Cairns and Other Prehistoric Monuments in Aberdeenshire and Banffshire, and a Short Cist at Bruceton, Alyth, Perthshire”. Proceedings of the Society of Antiquaries of Scotland, vol. 59, Nov. 1925, pp. 21-28, doi:10.9750/PSAS.059.21.28.