__h-index, or the Hirsch index__ is the scientometric indicator proposed in 2005 by Jorge Hirsch to assess scientific productivity. This index is calculated on the basis of citation distribution according to the formula:

- A researcher (a team of researchers) holds a Hirsch index h, if h of his Np articles are cited at least h times each, while the remaining (Np-h) articles are cited no more than h times each.

__The impact factor of a journal__ is the average quotation rate of one article. It is calculated by the formula:

- The ratio of the number of citations (over a year’s period) of articles published in the two preceding years to the total number of articles published in these two years.