When providing a citation in an argument, what do you consider a credible source?

In this day and age, when newspapers and the “mainstream media” are being supplanted by slanted internet blogs and doctored you-tube videos, what do you trust as a reliable resource? As a librarian, I am concerned with teaching critical thinking skills and “information literacy”, yet I see examples daily, both here and elsewhere, of people decrying valid scientific research or extolling undocumented garbage in support of their position. How do you evaluate what you read? What guidelines do you follow before claiming something is fact?

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