(1) Material source
Such sources happen naturally. Vegetables, poultry, and geographical resources, for instance. Geographical sources are such as stone sources, timber sources, outcrops, and so on.
(2) Written source
Newspapers, encyclopedias, diaries, reference Books, correspondence, documents in the Archives, government Gadgets, postage Stamps are examples of the written source. We can find new ideas about things, know about different research, etc. with the aid of these sources.
(3) Oral source
Oral sources are those sources which can be orally or orally registered.