Hutcheson, A. (1906) “Notice of a Jug of Peculiar Form found at Forfar, with an Additional Note on the Occurrence of Earthenware Jugs or Jars built into the Walls of Dwelling-houses in Scotland”, Proceedings of the Society of Antiquaries of Scotland, 40, pp. 352-355. doi: 10.9750/PSAS.040.352.355.