Papers include correspondence, manuscripts, and printed materials. Correspondence mostly concerns the Obʺedinenie in the 1950s. One of the manuscripts by Nikolaev is entitled"Ukrainsko-polśkie otnoshenii︠a︡ vo vremi︠a︡ sovet︠s︡ko-polśkoĭ voĭny 1920-1921 gg." Nikolaev's memoirs largely concern his activities as legal consultant to the Orthodox Church in Poland. Printed materials deal mostly with the Obʺedinenie.