Review the bibliography or references list at the end of that great book chapter or article. When you find a citation at the end of a book chapter or journal article you won't have Get it! buttons. Citation Linker is one tool to help you locate a citation by creating your own Get it! button. (Often there are links to references if you are reading online but if you are reading from paper you will need to locate the cited reference another way.)
Look at how the great article is indexed - subject headings, keywords, MeSH headings, etc.
Consult articles that have cited the great articles - see Citation tools below
Use "related article" or "more like this" features of various databases to get more
Paste article title in search box; review References (many with Get it! buttons), review Cited By documents, review Related Documents. Note: You can search within results of citing documents and related documents.