The original Scottish reference was Coinage of Scotland by Edward Burns written towards the end of the 19th century. B H I H Stewart, (Lord Stewartby) wrote 'The Scottish Coinage' in 1953 whilst still at school. I have a second impression copy from 1976. Coincraft did a Scottish, Irish, Channel Islands and IOM volume in 1999. The BNJ has articles on Scottish coins in volumes 19, 21, 22, 23, 26, 27, 28, 29, 33, 36, 37, 38, 39, 40, 41, 44, 48, 49, 50, 53, 57, 58, 59, 60, 61, 66, 67. There will be more from 2000 on, but my index only covers vols. 1-69.
I don't collect Scottish, so will have to think about other articles. There will be something in the Numismatic Chronicle and the Numismatic Circular. That's a start.