Cita APA (7a ed.)
Volker Perlick. Ray Optics, Fermat.s Principle, and Applications to General Relativity. Springer.
Cita estilo Chicago (17a ed.)
Volker Perlick. Ray Optics, Fermat.s Principle, and Applications to General Relativity. Berlín, Alemania: Springer.
Cita MLA (9a ed.)
Volker Perlick. Ray Optics, Fermat.s Principle, and Applications to General Relativity. Springer.
Precaución: Estas citas no son 100% exactas.