Pearl Growing: Front-End approach (used at beginning of search)
Research strategy that finds one ideal source that is similar to what you're researching.
The terms used to index that one perfect source are then used to track down other sources that have been indexed with the same terms.
Ex: Subject Headings
Bibliography Mining: Back-End approach (used once other sources have been acquired)
Research strategy that looks at the bibliographical references within a major academic work (article or book) that is on your topic.
A researcher then goes out and finds those sources, which contain more 'deposits' of historical discourse.
Example search: Dreyfus, by Harris, DC 354.H37 2010
Bibliographic essays may also be found at the end of some prominent works and textbooks which guide the researcher to other sources. Sometimes these take the form of "For Further Reading"
And of course, Literature Reviews of historical writings are invaluable.
Bibliography Mining is an effecient way to discover primary source material.
Often students will begin searching for primary sources by simply typing in a search term and 'primary documents.' This might work on occasion, and there are publications that are devoted to primary source material, but it is much more effective to collect citations from the bibliographical references within a text that is focused on your topic. This is often only accomplished by getting the physical item in your hands.
Acquiring the material is the tricky part.