"unreliable, adj. Not reliable; that cannot or should not be relied on." OED

Based on this definition of unreliable, unreliable sources should not be relied on. Sources are unreliable when (i) the author doesn’t have authority to write on the topic, (ii) the source contains plagiarized or uncited information, or (iii) the source contains inaccurate or false information. Unreliable sources can be books, journal articles, newspaper or magazine articles, websites, blogs, etc.

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1. Evaluating Sources