http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Lineĭnye different︠s︡ialʹnye operatory. English
τ. 1. Elementary theory of linear differential operators --
M.A. Naimark ; translated by E.R. Dawson ; english translation edited by W.N. Everitt.