When filing the patent, the applicant often refers to already published patent documents on the state of the art. During the examination process with patent offices, additional published patent documents can be found. These published patent documents are referred as cited patent documents.
Also, one's own patent is used within the life cycle of other companies patent filings, e.g. competitors. These are called citing patent documents.
The number of citing patent documents can be an indicator of the importance of the patent. A frequently cited patent can be an indication of a core technology.Citation search is also a powerful tool for research.
Citations are listed once you are looking at the detailed information.
If you would like to see all cited or citing documents from any publication you simply click the green button and they will appear in a new window. When you click "All cited" or "All citing" you will get all citations from the patent family, not just the publication you are viewing. Sometimes there are no citations documents visible, then you need to switch publication, click on any of the publications under "Also published as" to do this.
You can mouse over a patent number to see additional information, or you can click on a specific number to view it.