**2. Standardization in metrology**

Standards are considered as measurement references. The basic standards about metrology are the basis of the traceability which is defined as a measurement whereby the result can be related to a reference through an unbroken chain of calibrations. Using internationally standardized systems of units, Vocabulary of Metrology (VIM), Guide to the International Uncertainty Measurements (GUM), or Internationally Standardized Measurement Management Systems [3] helps to improve the reliability of the results.
