Letter from Paul Dirac, on a paper 'Wave equations in momentum space' by M Levy, to the Assistant Secretary of the Royal Society [D C Martin] Paper reference code: A89 Recommended 'in its present form' for publication in Proceedings. Written at 7 Cavendish Avenue, Cambridge [England]. [Published in Proceedings A, 1950]. Endorsed on recto as received 6 July 1950. 5 July 1950