“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”. 1938. Proceedings of the Society of Antiquaries of Scotland 72 (November): 122-28. https://doi.org/10.9750/PSAS.072.122.128.