Primary sources are materials that provide firsthand testimony or the closest evidence to a subject under investigation. Researchers often use these firsthand accounts of specific events, or direct investigations to understand events from the viewpoint of people living during that time period. Primary sources include letters, diaries, photographs, newspaper articles, and pamphlets.
To find primary sources via Google, try adding keywords like journals, papers, letters, documents, primary sources, or documentary history to your search terms. Primary sources can often be found on library, museum, and government websites.