Reid, J.J. 1885. Notice of two Vessels of Grey Stoneware (Bellarmines or Greybeards), one found full of Quicksilver in Shetland, the other at Eyemouth. Proceedings of the Society of Antiquaries of Scotland. 19, (Nov. 1885), 34–38. DOI:https://doi.org/10.9750/PSAS.019.34.38.