this is an opinion of a Russian historian in my translation

In reply to:

Political terminology (where an influence of Viking language must have been most noticeable) of the Old Russian language does not have traces of the Scandinavian influence. For example, see Jaroslav Mudrys Russian truth (medieval collection of law documents, composed in Kiev Rus vika) where the various status of Rus and the Slav is postulated.
The question who were Rus-vikings from the court of Rjurik (first king of Rus) is not that simple. It is quite possible, that the term "viking" / "varjag" should be understood as a designation of professional group - pirates and dealers who were not only Scandinavians, but also Slavs. It is remarkable, that in the east of Europe (modern Ukraine and Russia) vikings were not robbers but traders or simply travelled thought Slav lands to attack Byzantium (a way from varjag in Greeks), that allows some historians to assume that attacks of vikings in the Western and Southern Europe were characterised by religious war of pagan North-East against a Christian South-West. And in this war Scandinavians and east Slavs were allies.