Rinehart demands notes from Fairfax journalist Gina Rinehart. Photo: Claire Martin Fairfax Media's largest shareholder and Australia's richest person, Gina Rinehart, has taken legal action against Fairfax journalist Adele Ferguson in an apparent bid to force her to reveal her sources. At the request of Mrs Rinehart's private company, Hancock Prospecting, the Supreme Court of Western Australia has issued a subpoena demanding emails, text messages, notebooks, and any recordings of interviews that may have been made between Mrs Rinehart's eldest son, John Hancock, and Ferguson since September 2011. Ferguson faces jail if she does not comply with the subpoena by the end of the month. "As a journalist I will not ever reveal my sources, or do anything that may disclose the source of information that has been provided to me," she said. Mr Hancock, who is locked in a legal dispute with his mother over a trust that controls the family's iron ore riches, was the only member of Mrs Rinehart's immediate family to contribute on the record to Ferguson's unauthorised biography of Mrs Rinehart. Mrs Rinehart has a 15 per cent stake in Fairfax, publisher of the Herald, and a seat on the board of the Ten Network. She could not be reached and her friend Jack Cowin, who sits on the Fairfax board, declined to comment, as did Fairfax chairman Roger Corbett.