Former New York Times executive editor Jill Abramson has responded to claims that parts of her book are plagiarised.
The allegation about Merchants of Truth, which was released on Tuesday, was made by Vice News journalist Michael C Moynihan.
Ms Abramson says she takes the accusations "seriously" and will now "review the passages in question".
Merchants of Truth looks at how journalism has changed over the last decade.
In a Twitter thread, Mr Moynihan copied out excerpts from the book and compared them to passages published elsewhere.
He said he first started looking into the book after seeing "an egregious error" about a Vice News colleague, Arielle Duhaime-Ross, who was wrongly identified as transgender in an initial review copy.
After Ms Abramson corrected the mistake for the final publication, Mr Moynihan said he wanted to fact-check all three chapters about Vice because he felt they were "clotted with mistakes".
"While trying to corroborate certain claims, I noticed that it also contained... plagiarised passages," he wrote.
He then tweeted out a series of passages from the final copy of the book, alongside other articles and essays which he believed used very similar language.
Others in the media were quick to respond, with some saying the book was "a masterclass in how not to do journalism".
The following examples from the final book—not the galley—are only from the Vice chapters (I didn’t check the others). So let’s begin...Here is Abramson on Gavin McInnes (whom she interviewed) and the Ryerson Review of Journalism https://t.co/hx0XcyZ89k pic.twitter.com/qroN59gyVk— Michael C Moynihan (@mcmoynihan) February 6, 2019
Speaking soon after the accusations, Ms Abramson told Fox News that she "certainly didn't plagiarise in my book".
A few hours later she issued a new response on Twitter, promising to look into Mr Moynihan's claims.
"The attacks on my book from some in @vicenews reflect their unhappiness with what I consider a balanced portrayal," she wrote. "I endeavoured to accurately and properly give attribution to the hundreds of sources that were part of my research. I take seriously the issues raised and will review the passages in question."
Ms Abramson again defended her book in a statement to the Washington Post on Thursday, saying there were unintentional errors in attribution.
"My book has 70 pages of footnotes, and nearly 100 source citations in the Vice chapters alone, including the New Yorker, the Columbia Journalism Review, The Ryerson Review of Journalism, and a Masters' thesis, the sources from which Mr Moynihan says I plagiarized.
"The notes don't match up with the right pages in a few cases and this was unintentional and will be promptly corrected. The language is too close in some cases and should have been cited as quotations in the text. This, too, will be fixed."
Ms Abramson was fired from the New York Times in 2014 after "a series of issues".
In a statement following Ms Abramson's sacking, Times publisher Arthur Sulzberger Jr outlined some of those problems, including: "Arbitrary decision-making, a failure to consult and bring colleagues with her, inadequate communication and the public mistreatment of colleagues."