Some researchers use images or forms for a researcher or a book and document the source Is it sufficient to mention the source or need special permission?
According to me you need a special permission when you want to use in your article or book something from somebody's publication or somebody's unpublished work. It would be sufficient for example in such situation that you create your own material using information from somebody's publication.
There two types of images you can use in your research; copyrighted images and creative common image. With the forma you need the consent of the copyright own to use it for documentation and reproduction purposes; and with the latter, you don't need any permission, however, the source must be acknowledged.