Yahoo News explains: A guide to anonymous sources

Anonymous sources: it’s a hot topic, thrust back into the national spotlight this week with a bombshell New York Times op-ed from an unidentified “senior official in the Trump administration” claiming to be part of an effort to thwart the Trump White House. It was published a day after excerpts were revealed from an explosive book by veteran journalist Bob Woodward that paints a picture of a “nervous breakdown” of the Trump White House. His book is sourced using confidential interviews from current and former White House staffers. Both events have drawn “anonymous sources” back into the crosshairs of the president. When are anonymous sources used, anyway? Yahoo News explains.