Mikhail Sholokhov's claim to have written the epic novel "And Quiet Flows the Don," for which he received a Nobel Prize in literature, has been convincingly endorsed by a group of Scandinavian scholars who analyzed the book with the help of a computer.

Sholokhov's authorship of what is considered one, of the leading works of Russian prose has been the subject of rumors here and abroad from the moment the first part of the book appeared in 1928 when he was only 23. The suggestion that large parts of the manuscript were plagiarized finally surfaced in separate books published two years ago by an anonymous Soviet critic called "D" and Roy Medvedev, the dissident Soviet historian.

Both books said the probable "coauthor" of "The Quiet Don," as it is known in Russian, was Fyodor Kryukov, a talented Cossack writer with a colorful past who died in 1920 of typhus after fighting against the Bolsheviks in the Russian civil war. Sholokhov had taken Kryukov's unfinished manuscript, they asserted, and adapted it for publication.

Medvedev's study, by far the more careful and thorough of the two, said that Sholokhov served an important function by finishing the work - but that he should not be honored for a genius that was probably Kryukov's. The historian noted that a computer was used several years ago to establish definitively that the classics "The Iliad" and "The Odyssey" were written by Homer. He urged that a similar test be undertaken with "The Quite Don."

Now a team of four scholars - two Swedes and two Norwegians - using a CDC 3300 computer have done just that and reported their findings in the journal Scando-Slavica publshed in Copenhagen. Based on an analysis of work that is undisputedly Sholokhov's, extensive samples of Kryukov's writing and the text of "The Quiet Don" itself, the team's spokesman, Geir Kjetsaa, concluded:

"There is no reason to doubt that Kryukov worked at a major account of the dramatic events that took place before his eyes and in the course of which his own cossack people endured such privations. I am not even prepared to doubt that more or less detailed notes intended for use in a work of this kind may have come into Sholokhov's possession as part of the substantial material he used for his epic.

"However, the language seems to reveal that Sholokhov wrote his own work in which case the charge of plagiarism is null and void."

While not an outright refutation of the "D"-Medvedev arguments, the study essentially returns the situation to what it had been previously: Sholokhov wrote a masterpiece, a work far better than anything he was able to do subsequently, relying on a variety of local sources for graphic portrayals of events - which the writer himself acknowledged some time ago. Sholokhov, who will be 72 this spring and is in poor health, has never directly commented on the attacks against him.

In assessing styles, the Scandinavian study shows Sholokhov's use of words closely resembles "The Quiet Don" while Kryukov's is considerably different. The 15 most common parts of speech combinations appear in 49.4 per cent of the sentences in Sholokhov, and 49.6 in "The Quiet Don." The figure for Kryukov is only 40.8 per cent.

Even allowing for shifts in habits and changes in technique, the patterns remain basically the same: "Kryukov," asserts the report," is markedly dissimilar from Sholokhov in his writing and Sholokhov writes remarkably like the author of "The Quiet Don."

In the Scando-Slavica article, the scholars' spokesman Kjetsaa offers an academic's cautionary note by terming the analysis only a "pilot study" but one that nevertheless is a "forecast of the outcome" of the latest storm around "The Quiet Don."