Various sources contemporary to the war have been used to compile The Great War On This Day. The majority of events, additional notes, index entries and other appendices such as statistical data etc., have been primarily sourced from reprints of the following copyright-expired publications:
- Chronology of the War. Volumes I, II & III (1918-1920). Lord Edward Gleichen. Constable & Company, London.
- History of the Great War – Principle Events 1914-1918. (1922). The Historical Section of the Committee of Imperial Defence. HMSO, London.