As a self-publishing service, Blurb does not review, edit or monitor the content of books published using our services. This means we can't advise if it's legal for you to use content you don't own the rights to.
You may wish to google "fair use" policies for your country (as the rules vary by region). You may also want to look at the creative commons site for additional resources which might be available for use.
Blurb will investigate any copyright claims we receive. Please see our Copyright Policy, Section 12, for more information.