Foulis of Colinton., J. “An Inquiry into the Beverage of the Ancient Caledonians, and Other Northern Nations, at Their Feasts; And of Their Drinking Vessels”. Archaeologia Scotica, Vol. 1, Nov. 1793, pp. 12-25, http://journals.socantscot.org/index.php/arch-scot/article/view/381.