Columbia subject headings:
Paper--Preservation.
Harvard subject headings:
Manuscripts--Conservation and restoration
Paper--Preservation
Princeton subject headings:
Books--Conservation and restoration.
Laboratorii︠a︡ konservat︠s︡ii i restavrat︠s︡ii dokumentov (Akademii︠a︡ nauk SSSR)--History.
Manuscripts--Conservation and restoration.
Paper--Preservation.