When undertaking a Citation Analysis be aware of the following:
Publish or perish is a free tool that uses Google Scholar data to measure the amount of citations a particular article or report received from scholar. Though it can be bias given the fact that scholar favors those who make their articles open access due to it mainly linking to these kind of sites. Similarly it has a wide range of sources but no limit meaning that you could get less relevant format.
Scopus allows the citation anayalsisis of a wide variety of articles from 1996 to the present. It covers subjects from life sciensces, health sciences, physical sciences and social sciences and humanities. It can be accessed by Scopus via dkit library.