What is no source available ne demek?

"No source available" (kaynak mevcut değil) typically refers to a situation where information that is requested cannot be found or located. This can occur when trying to research information online, locate a missing document or locate a missing link. The message "no source available" may be displayed on a web page, database or document management system. It can also refer to instances where the original source of information is unknown or cannot be traced.