Mann, Ludovic McLellan. 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 (November):506-19. https://doi.org/10.9750/PSAS.038.506.519.