Ehrlich, Paul E.; Kim, seon-bu Comparison theory in Lorentzian and Riemannian geometry. (English) Zbl 1238.53047 Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 71, No. 12, e-Suppl., e211-e217 (2009). MSC: 53C50 53C20 53C22 PDF BibTeX XML Cite \textit{P. E. Ehrlich} and \textit{s.-b. Kim}, Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 71, No. 12, e211--e217 (2009; Zbl 1238.53047) Full Text: DOI OpenURL
Díaz-Ramos, J. Carlos; García-Río, Eduardo Curvature properties of geodesic celestial spheres in Lorentzian geometry. (English) Zbl 1159.53340 Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 63, No. 5-7, e481-e491 (2005). MSC: 53C50 53C20 PDF BibTeX XML Cite \textit{J. C. Díaz-Ramos} and \textit{E. García-Río}, Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 63, No. 5--7, e481--e491 (2005; Zbl 1159.53340) Full Text: DOI OpenURL
Díaz-Ramos, J. Carlos; García-Río, Eduardo; Hervella, Luis M. Comparison results for the volume of geodesic celestial spheres in Lorentzian manifolds. (English) Zbl 1077.53056 Differ. Geom. Appl. 23, No. 1, 1-16 (2005). MSC: 53C50 53C20 PDF BibTeX XML Cite \textit{J. C. Díaz-Ramos} et al., Differ. Geom. Appl. 23, No. 1, 1--16 (2005; Zbl 1077.53056) Full Text: DOI OpenURL