Many users, however, have criticized Paper Clip as an irritant, popping up too often with unwanted help.
Over the past decade, however, researchers have turned to other platforms to comment on and criticize papers that have been published in journals.
The N.F.L. has criticized previous papers published by the Center for the Study of Retired Athletes -- which identified similar links between on-field concussions and both later mild cognitive impairment and early-onset Alzheimer's disease -- and reasserted those concerns this week with regard to the paper on depression.
ZQ, JF, HM, JZ and MJ performed experiments; MM analyzed data and criticized the paper; MG contributed vital new reagents and criticized the paper; ZQ and GX designed the research, analyzed data and wrote the paper.
But before her novels emerged, Adler was best known for being an incisive critic and essayist for the New Yorker and the New York Times, though she quit her job as film critic for the latter after a year, and later criticized the paper for various editorial offenses in the introduction to her 2001 book, Canaries in the Mineshaft.
Pope Leo XIII, though he criticized the paper for other reasons, never objected to this rabid effort.
Monuments to Columbus are criticized for papering over the genocide of indigenous people.
Mr. Magazu called the Times article "character assassination" and sharply criticized the paper for publishing anonymous accusations without having direct contact with Mr. Witt or the woman.
In an e-mail message sent to The Associated Press on Sunday, Mr. Craig said the latest accusations were "completely false" and criticized the paper as practicing careless journalism.
Some readers, particularly Russia's intelligentsia, he said, have criticized the paper for being too sunny, too patriotic, too obsessed with sex and scandal.
