Cramond, W. 1897. Some Notes on Road Bills, with reference to a Collection of them, in three volumes, now exhibited; and Notes on the Casting from Abernethy Iron Works, now presented to the Museum. Proceedings of the Society of Antiquaries of Scotland. 31, (Nov. 1897), 224–227. DOI:https://doi.org/10.9750/PSAS.031.224.227.