I am currently a student at McGill University studying Pure Mathematics and having a research direction in mathematical pedagogy as well as mathematical physics+chemistry specifically in the realm of Non-linear/Linear PDEs used for many-bodies problem and density functional theory. I was wondering, aside from V.I.Arnold’s Lectures on Partial Differential Equations, is there an esteemed book on Partial Differential Equations from Soviet/Russian School of Thought for mathematics? I am trying to find some references about great russian books on this topic but, it is quite hard.