There are reliable sources that indicate that an official flag was declared by the Ukrainian People's Republic in 1918 is blue–yellow. Some sources mention that the yellow–blue was adopted by Tsentralna Rada on 22 March 1918. Other sources point out that no hard proof of "such" decision exists. Instead, they refer to the decision on the Fleet Flag, which was set to be light blue–yellow as an indication that the official flag was light blue–yellow. Also were adopted other service flags of the Ukrainian People's Republic.