Skinner & Stacke 1922, p. 6. Skinner, H. T.; Stacke, H. Fitz M. (1922). Principal Events 1914–1918. History of the Great War Based on Official Documents (online scan ed.). London: HMSO. OCLC17673086. Retrieved 6 March 2014 – via archive.org.
worldcat.org
Skinner & Stacke 1922, p. 6. Skinner, H. T.; Stacke, H. Fitz M. (1922). Principal Events 1914–1918. History of the Great War Based on Official Documents (online scan ed.). London: HMSO. OCLC17673086. Retrieved 6 March 2014 – via archive.org.