The Hydra was a magazine produced by the patients of the Craiglockhart War Hospital, noteworthy for having been edited at one time by Wilfred Owen, and for including poems by Siegfried Sassoon. The magazine was headquartered in Edinburgh. Another editor was Black Watch officer James Bell Salmond, who went on to be editor of The Scots Magazine and was later the Keeper of Muniments at the University of St Andrews. In 1918 George Henry Bonner became the editor. The magazine ceased publication the same year.
- "Recovering Hydra". Oxford Today. 6 October 2014. Retrieved 31 October 2015.
- "MS 2 Lieutenant Patrick Wright Anderson, Black Watch, RFC and RAF". Archive Services Online Catalogue. University of Dundee. Retrieved 7 September 2018.
- "Publications of War". Oxford University. Retrieved 31 October 2015.
- Scanned copies of The Hydra at the First World War Poetry Digital Archive