1. BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML, Guide to the expression of uncertainty in measurement (GUM), second ed., ISO, Geneva, Switzerland, 1993.
2. DIN 1319, Fundamentals of metrology – Part I: basic terminology, Berlin, Beuth, 1995.
3. http://bipm.kcdb.org.
4. Theoria combinationis observationum erroribus minimis obnoxiae, Gottingen, (1823) English translation by Stewart;Gauss,1995
5. Probability in metrology;Rossi,2008