1. Convention of the Meter. Accessed Dec 2010. http://www.bipm.org/en/convention
2. BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML (1993) International vocabulary of basic and general terms in metrology, 2nd edn. ISO, Geneva
3. BIPM, IEC, ISO, OIML (1983) International vocabulary of basic and general terms in metrology. ISO, Geneva
4. BIPM, IEC, IFCC, ILAC, ISO, IUPAC, IUPAP, OIML (2008) International vocabulary of metrology—basic and general concepts and associated terms (VIM), 3rd edn JCGM vol 200. Accessed Dec 2010. http://www.bipm.org/vim
5. Dedekind R (1893) Was sind und was sollen die Zahlen? Friedrich Vieweg und Sohn, Braunschweig, 1893 [English translation: The nature and meaning of numbers. Accessed Dec 2010. http://www.archive.org/details/essaysintheoryof00dedeuoft ]