1. BIPM, IEC, IFCC, ILAC, IUPAC, IUPAP, ISO, OIML (2008) The International Vocabulary of metrology—Basic and general concepts and associated terms (VIM), 3rd edn. JCGM 200, entry 2.42 http://www.bipm.org/en/publications/guides/vim.html
2. BIPM, IEC, IFCC, ILAC, IUPAC, IUPAP, ISO, OIML (2008) The International Vocabulary of metrology—Basic and general concepts and associated terms (VIM), 3rd edn. JCGM 200, entry 2.41 Note 1 http://www.bipm.org/en/publications/guides/vim.html
3. BIPM, IEC, IFCC, ILAC, IUPAC, IUPAP, ISO, OIML (2008) The International Vocabulary of metrology—Basic and general concepts and associated terms (VIM), 3rd edn. JCGM 200, entry 1.9 http://www.bipm.org/en/publications/guides/vim.html
4. BIPM, IEC, IFCC, ILAC, IUPAC, IUPAP, ISO, OIML (2008) The International Vocabulary of metrology—Basic and general concepts and associated terms (VIM), 3rd edn. JCGM 200, entry 2.40 http://www.bipm.org/en/publications/guides/vim.html
5. BIPM, IEC, IFCC, ILAC, IUPAC, IUPAP, ISO, OIML (2008) The International Vocabulary of metrology—Basic and general concepts and associated terms (VIM), 3rd edn. JCGM 200, entry 3.2 http://www.bipm.org/en/publications/guides/vim.html