Mann, L. M. (1904) “Notes (1) on Two Tribula or Threshing-Sledges, having their under surfaces studded with rows of chipped flints, for threshing corn on a threshing-floor, from Cavalla in European Turkey, now presented to the Museum; and (2) on Primitive Implements and Weap”, Proceedings of the Society of Antiquaries of Scotland, 38, pp. 506–519. doi: 10.9750/PSAS.038.506.519.