CalPERS, the nation's largest public pension fund, is joining other large investors in News Corp that are calling for the ouster of Rupert Murdoch and his sons James and Lachlan from the company's board of directors. CalPERS has questioned the Murdochs' stewardship of the company following revelations that its now-defunct News of the World routinely hacked the voicemail of politicians and celebrities and that its European edition of the Wall Street Journal may have engaged in an unethical scheme to enhance its circulation figures. Nevertheless, the investors are enterting what many analysts believe is an unwinnable battle. The Murdochs have so set up voting rights that while they may own only about 12 percent of the stock, they control about 40 percent of the votes.