books.google.it - Each of the articles is accompanied by the editor's notes. In addition, each article has been studied (and, in parts, corrected) by modern Russian mathematicians and appears with their commentaries.This deals with the theory of systems of partial differential equations and is central to the modern general...http://books.google.it/books/about/I_G_Petrowsky_Selected_Works.html?hl=it&id=2XTFlNZIVXcC&utm_source=gb-gplus-shareI. G. Petrowsky Selected Works
