Formerly pretty good free resource for academic citations now turned into a giant pile of steamy hot garbage by the incredible asswipes at Chegg, a corporate name that mostly calls forth the image of a debilitating sexually transmitted infection.
Recommend using instead: https://www.scribbr.com/citation/generator. At least until they also start demanding your firstborn daughter for each citation.
It is! I taught research at the grad and doctoral level and Zotero was the best by a long shot. SciWheel is a close second.
I hope the Devil comes for EndNote soon, it is awful and has been awful for a long time.