The World War One Source Book. Philip J. Haythronthwaite. 400 pages, Brockhampton Press, 1998. The information on weapons and equipment is still valid since the war occurred only a couple of years earlier. There is also good data on the status of the various armies in 1914.
Uniforms of the World. Richard, Herbert Knotel & Herbert Sieg. 480 pages, Scribner's, 1980.
A Concise History of the Balkan Wars, 1912-13. Hellenic (Greek) General Staff. 360 pages in English!, Army History Directorate, 1998. Covers as can be expected mainly Greek Operations.
An Index of Events in the Military History of the Greek Nation. Hellenic (Greek) General Staff. 500 pages in English!, Army History Directorate, 1998.
Armies of The World, 1854-1914. David Woodard. 180 pages, Putnam & Sons, 1978.
The Evones. Yannis Mylonas. 330 pages in English, Floros Publishing, Athens, Greece, 1997. Covers the history of the elite rifle and light infantry battalions of the Greek Army. The author also assisted on "Weapons of the Balkan Wars, 1912-13" which was published by the War Museum in Athens but I have been unable to find that book.
Uniforms of the Balkan Wars. Yannis Mylonas. 239 pages in Greek, ?? Athens, ~1999. A beautiful book full of color plates of the combatants uniforms. Text is in Greek but nationalities are easy to identify. I am thankful that my Greek clients provided a translation.
Bulgarian Military Uniforms During the Balkan Wars. I am unable to provide additional data on the publication. It is a Squadron-Signal format booklet of 48 pages with color uniform plates. It was written in Bulgarian with an English Translation section. I was only able to obtain a copy of the English text and Black and White uniform copies. I lost the bid on an ebay auction but the winner was kind enough to provide me with the copy. It would be well worth a search.
Balkan Wars : Prelude to Disaster, 1912-13 a lead article by Richard Lechowitz and a game published in "Strategy and Tactics" magazine, issue #164, Nov 1993.
A History of the Balkans. Ferdinand Schevill. 540 pages, Dorset Press, NY, 1991.
Military Uniforms, 1686-1918. Rene North. 156 pages, Bantam Books, 1971.
The Balkans, 1815-1914. L.S. Stravrianos. 131 pages, Holt, Rhinehardt Press, 1963. Contains good background information as to the cause of the war.
Serbian Military Uniforms, 1808-1918. Pavle Vasic. The Serbian Unity Congress Website.