There are a large number of Dostoyevsky's novels and stories on the [Internet Archive](https://archive.org/) site, many of them in public domain and free to download in PDF format. I recommend PDF because that way you get actual page views of the printed books, and you know the text has not been cut, edited or otherwise messed with. Also, you can cite passages by volume, date and page. Just do a meta search on the name "Dostoyevsky" and then click the box that says "always available." You can download what shows up.