Citation chaining is the process by which you identify one solid information source, such as an article relevant to your topic, and mine its list of references for additional useful resources. Backward chaining or snowball searching is looking for the cited articles that came before the one you are examining. (Some may be critical; others may be obsolete.
Forward chaining is locating the more recent writing of others who have cited the article. The moving backward and forward creates a chain of linked relevant literature. This is simple to do in Google Scholar. You can also personalize Google Scholar to link to articles to which the library has access.