Aulis Oja (3 February 1910 Turku – 10 September 1976 Helsinki) was a Finnish historian.
Niilo Paavo Virtanen (18 March 1905 Tampere – 19 August 1977 Helsinki) was a Finnish librarian and literary researcher.
I was unable to find any kind of repository. My guess is that perhaps Virtanen catalogued some of Oja's work. I would say if that is the only source listed, it would qualify as Unsourced. It certainly is not specific enough to be useful. Need some of our Finnish friends to weigh in.