Question: During which year(s) did the Russian army withdraw from the Caucasus front?
About the article "World War I", section "New states under war zone".

Candidate passages:
 Caucasus Front (Russian Republic), the successor organization to the Imperial Russian Caucasus Army  
 11th Army (Soviet Union) (1918-1921), formed October 3 1918 from the Northern Caucasus Army Its successor, the Red Banner Caucasus Army (1921-1935), which was named the Independent Caucasus Army until August 1923 Its successor, the Transcaucasian Military District Transcaucasian Front, a Soviet army group of World War II Caucasus Front, a Soviet army group of World War II  
 Russian Caucasus Forces (before 1865), a variety of formations with various names including (in 1857-1865) Caucasus Army  Caucasus Military District, the successor organization to this army Russian Caucasus Army (World War I), the Russian army on the Caucasus front in World War I (July 1914 - April 1917)  
At the beginning of World War I Yudenich was appointed Chief of Staff of the Russian Caucasus Army.
The detachment's operations included the Battle of Sarıkamış, a victory against Enver Pasha of the Ottoman Empire.
In January 1915, Yudenich was promoted to General of Infantry, and replaced Count Illarion Ivanovich Vorontsov-Dashkov as commander of the Caucasus Campaign.
Yudenich tried to exploit the Turkish defeat by attacking into Turkish territory, specifically around Lake Van during the Siege of Van.
While the Russians did capture Van in May 1915, they were forced to withdraw from the city two months later.
The Ottoman 3rd Army re-occupied Van in August.
At this time, Grand Duke Nicholas, having been removed from command of all of Russia's armies, was put in charge of the Caucasus region.
Yudenich was given a free hand by the Grand Duke and, in September, the Russians retook Van and re-established the Administration for Western Armenia in June 1916.
Fighting back and forth around this region continued for the next 14 months without a clear victory for either side.
In 1916 Yudenich successfully carried out an offensive, winning the Battle of Erzurum (1916) and the Trebizond Campaign.
In the summer of that year, his forces fought off a Turkish counter-attack culminating in the Battle of Erzincan (despite the presence of Turkish General Mustapha Kemal).
During this battle, Yudenich was awarded the Order of St. George (2nd degree), the final time this decoration was awarded in the Russian Empire.
Following the February Revolution, in 1917 Yudenich was appointed commander of the Caucasus Front, but in May the Russian Provisional Government removed him from command for insubordination, and on the direct orders from Alexander Kerensky, he retired from the army.
Yudenich then relocated from Tbilisi to Petrograd, where he supported the Kornilov Revolt. 
On December 5 1917 the Armistice of Erzincan was signed between the new Soviet government of Russia and the Turkish Third Army, formally ceasing fighting in the Caucasus.
Nevertheless, the Turks continued some offensive operations, taking advantage of the fact that the Caucasus Front had effectively ceased to exist as a cohesive military force.
Such resistance as the Turks met was offered by Armenian volunteer militia units.
This was followed on March 3, 1918 by the Treaty of Brest-Litovsk ending all hostilities with the Turks.
Since the Caucasus Front dissolved, it did not have a true successor organization.
The Army of the North Caucasus, which was renamed 11th Army on October 3, 1918, constituted the main Soviet army in the area during the Russian Civil War.