Quality management system the early signaling of problems via a continual improvement cycle. In the 21st century, QMS has tended to converge with sustainability and transparency initiatives, as both investor and customer satisfaction and perceived quality is increasingly tied to these factors. Of QMS regimes, the ISO 9000 family of standards is probably the most widely implemented worldwide – the ISO 19011 audit regime applies to both, and deals with quality and sustainability and their integration. Other QMS, e.g. Natural Step, focus on sustainability issues and assume that other quality problems will be reduced as result of the systematic thinking, transparency, documentation and
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