Dakers, C. “Notes on Scottish Coins: (1) Rex Scottorum Pennies of David II.; (2) Edinburgh Light Groats of Robert III.; (3) Some James II. Groats of the Third Variety of the Fleur-De-Lis Groats; And (4) Gilbert Kirkwood’s Mark on a Gold Coin of James V”. Proceedings of the Society of Antiquaries of Scotland, Vol. 72, Nov. 1938, pp. 122-8, http://journals.socantscot.org/index.php/psas/article/view/8087.