After posting weak fourth quarter and fiscal 2013 results, Barnes & Noble disclosed in filings Thursday morning that it has amended its credit agreement with several of its banks that will place limits and conditions on B&N’s dividend payments and stock buyback activities. The company also revealed that it will be late in filing its 10-K report due to an ongoing review of previous filings. B&N had said as part of its release of its year-end results that it was conducting such a review and that it may need to make some restatements.