Anderson, J. 1896. Notes on a Deposit of Flints worked to a leaf-shape, found at Bulwark, Old Deer, Aberdeenshire; exhibited by Alexander Gray, New Deer. Proceedings of the Society of Antiquaries of Scotland. 30, (Nov. 1896), 346–351. DOI:https://doi.org/10.9750/PSAS.030.346.351.