The LIGO Scientific Collaboration; the Virgo Collaboration (2007). "The Kerr spacetime: A brief introduction". p. 13, below eq. 52. arXiv:0706.0622v3 [gr-qc].
Berman, Marcelo. "Energy of Black Holes and Hawking's Universe" in Trends in Black Hole Research, page 148 (Kreitler ed., Nova Publishers 2006).
Stephani, Hans et al. Exact Solutions of Einstein's Field Equations (Cambridge University Press 2003). See page 485 regarding determinant of metric tensor. See page 325 regarding generalizations.
Debney, G. C.; Kerr, R. P.; Schild, A. (1969). "Solutions of the Einstein and Einstein-Maxwell Equations". Journal of Mathematical Physics. 10 (10): 1842–1854. Bibcode:1969JMP....10.1842D. doi:10.1063/1.1664769. Especially see equations (7.10), (7.11) and (7.14).
Bardeen, James M.; Press, William H.; Teukolsky, Saul A. (1972). "Rotating Black Holes: Locally Nonrotating Frames, Energy Extraction, and Scalar Synchrotron Radiation". The Astrophysical Journal. 178: 347. Bibcode:1972ApJ...178..347B. doi:10.1086/151796.
Debney, G. C.; Kerr, R. P.; Schild, A. (1969). "Solutions of the Einstein and Einstein-Maxwell Equations". Journal of Mathematical Physics. 10 (10): 1842–1854. Bibcode:1969JMP....10.1842D. doi:10.1063/1.1664769. Especially see equations (7.10), (7.11) and (7.14).
Bardeen, James M.; Press, William H.; Teukolsky, Saul A. (1972). "Rotating Black Holes: Locally Nonrotating Frames, Energy Extraction, and Scalar Synchrotron Radiation". The Astrophysical Journal. 178: 347. Bibcode:1972ApJ...178..347B. doi:10.1086/151796.