The Index was compiled during the late 19th century and indexing does not follow modern principles.The references are in Finnish and Swedish according to the original language. There is a link to the newspaper if it has been digitised.There can be spelling errors in the reference texts.
You can read more about the history of the article index in the Scripta Selecta-blog of the National Library (in Finnish).
The Translocalis-project has created clippings from article index for searching and further analysis.