ISO 9000 addresses to which the certificate refers. An ISO 9001 certificate is not a once-and-for-all award but must be renewed at regular intervals recommended by the certification body, usually once every three years. There are no grades of competence within ISO 9001: either a company is certified (meaning that it is committed to the method and model of quality management described in the standard) or it is not. In this respect, ISO 9001 certification contrasts with measurement-based quality systems. The ISO 9000 standard is continually being revised by standing technical committees and advisory groups, who receive feedback from those professionals who
International Standard Book Number on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967, based upon the 9-digit Standard Book Numbering (SBN) created in 1966. The 10-digit ISBN format was developed by the International Organization for Standardization (ISO) and was published in 1970 as international standard ISO 2108 (the SBN code can be converted to a ten-digit ISBN by prefixing it with a zero digit "0"). Privately published books sometimes appear without an ISBN. The International ISBN agency sometimes assigns such books ISBNs on its own initiative. Another identifier, the International Standard Serial Number