How can I find the DOI for an old mathematical paper which is not in English?
As others have said, not every (old) article has a DOI or a URL. However, in mathematics every article since 1940 has an MR number which uniquely identifies it. So go to mathscinet and look up this article. I just did, it has MR number MR0844292. The bibliographical information on mathscinet (like the transliteration of the author's name) would also be considered the "canonical information".