The structure of each science solids to reference sources and each science has specific research sources which are useful tool for the scientists and librarians. It helps them to find the special information and guides the one who search for information as correction of the information. And helps them to know where and how they can find the answers of questions which are necessary to reply. The following scheme has the knowledge of around this subject and it gains characteristic Dr. Qasem Safi's book which is "Reference Source (General)".
)