Hirsch-type approach to the 2nd generation citations

Scientific papers are usually assessed by a number of direct citations. The number of citations received by direct citations (2nd generation citations) has been considered as an alternative criterion of evaluation. Such an approach overrates the papers, which received citation(s) in one or in a few very highly cited papers. Hirsch-type approach to the 2nd generation citations suggested by Schubert was used to combine the impact and quantity of 1st generation citations into one number.