Lobanova notes that Roslavets lists 6 violin sonatas in the worklist he compiled in 1940 and that 5 of them had either been found or could perhaps be accounted for she refers to the preface of the edition of the 2nd violin sonata which I should I admit go read no reason is given why the 6th is not say still lost and the sonata enclosed not some other work e g a work of youth that Roslavets simply did not list