In EBSCOhost databases, you can find some tools on the right side of each result. Click "cite" and find the citation format of this source in many different referencing style. Scroll down and find Harvard style. You can either copy it or export the details and use it in other reference management tool, e.g. Zotero or Word reference tool.
In JSTOR database, you can also find citation tool on the right side of each result. You can view, email, export and save the item's citation. Please note that the citation tool in JSTOR provides only information you need when writing the reference and citation. You must re-write them in the correct Harvard referencing format in your essay.
In Britannica School Online database, you can find some tools at the top right side of each article. Among those tools, click the one with a tick in a square box. Select Harvard as your citation style and then you will see the reference information appears at the bottom.