This is quite interesting while the webpage itself is obviously unreliable the actual document being cited doesnt appear to have been produced by the same people responsible for the page rather judging by the formatting and citations it seems to be a chapter from a book or a journal article of some sort that has merely been uploaded there  Unfortunately I dont have the expertise to determine whether LopukhovskyKavalerchik are a reliable source in their own right while they certainly dont have the name recognition that Krivosheev does they have written what appear to be actual nonselfpublished books eg httpwwwozonrucontextdetailid and may thus be a legitimate alternative viewpoint to be considered My suggestion would be to ask for assistance on evaluating these authors at WTMILHIST andor WPRSN perhaps someone who edits more on this topic will have more insight into whether theyre serious historians