Kerr, Roy P. (1 September 1963). "Gravitational Field of a Spinning Mass as an Example of Algebraically Special Metrics". Physical Review Letters. 11 (5). American Physical Society (APS): 237–238. Bibcode:1963PhRvL..11..237K. doi:10.1103/physrevlett.11.237. ISSN0031-9007.
Kerr, Roy P. (1 September 1963). "Gravitational Field of a Spinning Mass as an Example of Algebraically Special Metrics". Physical Review Letters. 11 (5). American Physical Society (APS): 237–238. Bibcode:1963PhRvL..11..237K. doi:10.1103/physrevlett.11.237. ISSN0031-9007.
Kerr, Roy P. (1 September 1963). "Gravitational Field of a Spinning Mass as an Example of Algebraically Special Metrics". Physical Review Letters. 11 (5). American Physical Society (APS): 237–238. Bibcode:1963PhRvL..11..237K. doi:10.1103/physrevlett.11.237. ISSN0031-9007.