Hi
Books on the Imperial Russian Air Service during WWI include:
'The Imperial Russian Air Service - Famous Pilots and Aircraft of World War I' by Alan Durkota, Thomas Darcey and Victor Kulikov, Flying Machine Press 1995.
'The Russian Military Air Fleet in World War I - Volume 1: A Chronology 1910-1917' by August G. Blume, Schiffer Military History 2010. And:
" " " - Volume 2: Victories, Losses, St. George Awards, Romanian and French Awards'
'Osprey Aircraft of the Aces - 111, 'Russian Aces of World War I' by Victor Kulikov.
If you are interested in Russian Aircraft Markings there are four volumes of 'Russian Aviation Colours 1909-1922' by Marat Khairulin & Boris Stepanov.
I hope that helps.
Mike