You can find the original paper by Hirsh who introduced the H (after his name) index here 

http://www.pnas.org/content/102/46/16569.full.pdf">JE

Here is a page that links to the article that describes the creation of the h-index as well as how to calculate it.

http://researchguides.uic.edu/c.php?g=252299&p=1683205

there is a procudure please read scopus ha explains well

This may be helpful

https://scholar.google.com/intl/en/scholar/metrics.html#metrics

That is  interesting to know

Its nice reply by Dietrich Rordorf to this question.