U.S. yellow-pages publisher R.H. Donnelley Corp filed for Chapter 11 bankruptcy protection on Thursday, court documents showed.

In a filing with the U.S. Bankruptcy Court for the District of Delaware, the company listed total assets of about $11.88 billion and total debts of about $12.37 billion.

R.H. Donnelley's largest unsecured creditors include Bank of New York Mellon and U.S. Bancorp .

The company said last week that it was seeking support of its bank lenders as part of a potential comprehensive debt restructuring plan, after it missed a $55 million interest payment on a series of senior unsecured notes due on April 15.

R.H. Donnelley exercised a 30-day grace period for the payment and then asked creditors for a forbearance until May 28.

Competitor Idearc Inc filed for bankruptcy protection in March and said it had agreed with its lenders to reduce its total debt from around $9 billion to $3 billion in secured bank loans.

The case is In re: R.H. Donnelley Corp., U.S. Bankruptcy Court, District of Delaware, No. 09--11833.

(Editing by Muralikumar Anantharaman)