Redundancies
NOR and RS: Description of primary, secondary, and tertiary sources
From WP:RS:
Three classes of sources exist, each of which can be used within Wikipedia:
- Primary sources are documents or people very close to the situation you are writing about. An eyewitness account of a traffic accident published in a newspaper, and the White House's summary of a president's speech are primary sources. Primary source material that has been published by a reliable source may be used for the purposes of attribution in Wikipedia, but only with care, because it's easy to misuse primary sources. The Bible cannot be used as a source for the claim that Jesus advocated eye removal (Matthew 18:9, Mark 9:47) for his followers, because theologians differ as to how these passages should be interpreted. Edits that rely on primary sources should only make descriptive claims that can be checked by anyone without specialist knowledge.
- Secondary sources are documents or people that summarize other material, usually primary source material. These are academics, journalists, and other researchers, and the papers and books they produce. A journalist's analysis of a traffic accident, or the analysis and commentary of a president's speech, are secondary sources. Wikipedia articles should rely on reliable, published secondary sources wherever possible. This means that we only publish the opinions of reliable authors, and not the opinions of Wikipedians who have read and interpreted primary source material for themselves.
- Tertiary sources are reference books such as dictionaries, general encyclopedias and almanacs. These sources generally lack adequate coverage of the topic to be considered comprehensive where arguments are subtle and nuanced. They generally do not discuss and evaluate alternative interpretations. Tertiary sources used for basic facts such as names, spellings, locations, dates and dimensions do not need to be cited. Tertiary sources used for more substantive facts do need to be cited. Some tertiary sources are more reliable than others, and within any given tertiary source, some articles may be more reliable than others. For example, articles signed by experts in Encyclopaedia Britannica and encyclopedias of similar quality can be regarded as reliable secondary sources instead of tertiary ones. Unsigned articles may be less reliable, but they may be used so long as the encyclopedia is a high quality one.
From WP:NOR:
- Primary sources are documents or people very close to the situation being written about. An eyewitness account of a traffic accident is a primary source. The White House's summary of a president's speech is a primary source. Primary sources that have been published by a reliable source may be used in Wikipedia, but only with care, because it's easy to misuse them. For that reason, anyone—without specialist knowledge—who reads the primary source should be able to verify that the Wikipedia passage agrees with the primary source. Any interpretation of primary source material requires a secondary source.
Examples of primary sources include archeological artifacts; photographs; newspaper accounts which contain first-hand material, not merely analysis or commentary of other material; historical documents such as diaries, census results, video or transcripts of surveillance, public hearings, trials, or interviews; tabulated results of surveys or questionnaires; written or recorded notes of laboratory and field experiments or observations; and artistic and fictional works such as poems, scripts, screenplays, novels, motion pictures, videos, and television programs.
- Secondary sources draw on primary sources in order to make generalizations or original interpretive, analytical, synthetic, or explanatory claims. A journalist's analysis or commentary of a traffic accident based on eye-witness reports is a secondary source. A New York Times analysis and commentary on a president's speech is a secondary source. An historian's interpretation of the decline of the Roman Empire, or analysis of the historical Jesus, constitute secondary sources. Wikipedia articles should rely on reliable, verifiable, published secondary sources wherever possible. This means that we present verifiable accounts of views and arguments of reliable scholars, and not interpretations of primary source material by Wikipedians.
- Tertiary sources are publications, such as encyclopedias, that sum up other secondary sources, and sometimes primary sources. Wikipedia is a tertiary source.