Hawking's signed thesis, wheelchair auctioned in London A copy of Stephen Hawking's PhD thesis signed in a shaky hand features the highlight of a new auction of the British physicist's personal items in London. One of Hawking's early wheelchairs, a copy of his bestselling book "A Brief History of Time" signed with a thumbprint and a script from TV series "The Simpsons" are also among the 22 lots on sale at Christie's auction house.