Of course, this merely reflects normal practice. At the same time, electronic, multi-media publishing has emerged as an alternative to conventional publishing on paper. They allow non-linear progression through the text. Sound and moving images can be added. Sections can be copied into new documents.
Electronic bookmarks are less convenient than bits of paper.
Adding personal notes to electronic documents is difficult. We have been investigating ways of resolving these difficulties by publishing material as ordinary, printed documents that can be read in the normal way, enjoying the usual benefits of readability, accessibility and portability. However, when observed by a camera connected to a computer, they acquire the properties of electronic documents, blurring the distinction between the two modes of operation and giving a richer presentation than that afforded by either separate medium. The two parts can now be united and a number of applications have been investigated. Sections of the documents can be captured in electronic form, edited, printed and animated in the same way.