Use to mark an external hyperlink for which there may be a valid replacement or available archived version as being dead, but when the determination requires additional or extensive research. Articles using this template will be auto-categorized into Articles with dead external links. Preferable to outright removal of links when there is doubt about possible future usefulness or when the link forms part of a reference (referenced works should not be removed simply because the links are dead, in order to maintain encyclopedic integrity - such works could additionally exist in print or on microfilm, for example).