The White House search for a successor to Federal Reserve Chairman Alan Greenspan, who is scheduled to retire in January, has intensified.... [T]he three candidates cited most frequently have been economists Martin Feldstein of Harvard University, Glenn Hubbard of Columbia University and Ben Bernanke, chairman of President Bush's Council of Economic Advisers. But the White House also is looking at other candidates, including former Bush adviser Lawrence Lindsey, said several people familiar with the process. They said the White House hasn't rejected the three main candidates but doesn't want to limit its choice prematurely. There appears to be no clear...