Ritchie, J. 1921. Relics of the Body-Snatchers: Supplementary Notes on Mortsafe Tackle, Mortsafes, Watch-houses, and Public Vaults, mostly in Aberdeenshire. Proceedings of the Society of Antiquaries of Scotland. 55, (Nov. 1921), 221–229. DOI:https://doi.org/10.9750/PSAS.055.221.229.