Our citations and authorship data both come from Microsoft Academic Graph (MAG).
Their data in turn is derived from automatic article crawling combined with AI-based author and institution disambiguation techniques. This is the same approach used by Scopus and Google Scholar. MAG's coverage and accuracy is broadly similar to these other services.
One great thing about MAG is that their data is open, so you can share it with anyone.
MAG recently stated they will be discontinuing their data source at the end of 2021. Unsub will be building a replacement (announcement).