Warren Buffet Gives Investing Tips In Letter To Berkshire Hathaway Inc. ShareholdersWarren Buffet Gives Investing Tips In Letter To Berkshire Hathaway Inc. ShareholdersOMAHA, Neb. (AP) — Warren Buffett is offering a refresher course on his approach to investing in his annual letter to Berkshire Hathaway Inc. shareholders.Associated PressAssociated Press