Locating primary sources for historical research is an iterative process. It often involves consulting the secondary sources, tracking down primary sources used by others, going back to the literature as new names, events, and concepts emerge, then back to the tracking down potential primary documents.
For historians, some of the most fruitful searching happens in the library catalog. When searching, keep the following in mind.
Search for authors - Individuals, organizations, and government branches/agencies can all be authors, and can be searched in library catalogs. Results might include autobiographies, published correspondence and diaries, interviews, government reports, hearings, and studies, periodicals and bulletins, and archival collections.
Know your subject headings - It helps to get to know how subject headings are used to describe your topic. For example, the subject headings Cuban Americans and Cubans--United States have slightly different meanings, and both could be useful for studying Americans of Cuban origin or Cubans in the United States, respectively.
The duPont-Ball library subscribes to the following primary source databases that may be helpful in research on the Holocaust.
Many museums and archives digitize parts of their collections and make them freely available online. Below is a sample of digital collections that have material on the Holocaust.