Zotero is a larger citation management software. It comes with benefits like being able to link into Word and Google Docs. Zbib is a mini version of Zotero that works similarly to other online citation generators, but it does not have adds or paywalls. The larger Zotero is slightly more complex and has a larger learning curve, but also provides better options for organizing your research. If your only concern is getting a few correct citations, Zbib should do the trick.