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P. Ojeda and H. Rosu (2006), "Supersymmetry of FRW barotropic cosmologies", International Journal of Theoretical Physics, 45 (6): 1191–1196, arXiv:gr-qc/0510004
Their solutions can be found in Rosu, Haret C.; Mancas, Stefan C.; Chen, Pisin (2015-05-05). "Barotropic FRW cosmologies with Chiellini damping in comoving time". Modern Physics Letters A. 30 (20): 1550100. arXiv:1502.07033
Elcio Abdalla; Guillermo Franco Abellán; et al. (11 Mar 2022), "Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies", Journal of High Energy Astrophysics, 34: 49, arXiv:2203.06142v1.
Secrest, Nathan J.; Hausegger, Sebastian von; Rameez, Mohamed; Mohayaee, Roya; Sarkar, Subir; Colin, Jacques (2021-02-25). "A Test of the Cosmological Principle with Quasars". The Astrophysical Journal. 908 (2): L51. arXiv:2009.14826. doi:10.3847/2041-8213/abdd40.
McCrea, W. H.; Milne, E. A. (1934). "Newtonian universes and the curvature of space". Quarterly Journal of Mathematics. 5: 73–80. Bibcode:1934QJMat...5...73M. doi:10.1093/qmath/os-5.1.73
See pp. 351ff. in Hawking, Stephen W.; Ellis, George F. R. (1973), The large scale structure of space-time, Cambridge University Press. The original work is Ehlers, J., Geren, P., Sachs, R.K.: Isotropic solutions of Einstein-Liouville equations. J. Math. Phys. 9, 1344 (1968). For the generalization, see Stoeger, W. R.; Maartens, R; Ellis, George (2007), "Proving Almost-Homogeneity of the Universe: An Almost Ehlers-Geren-Sachs Theorem", Astrophys. J., 39: 1–5, Bibcode:1995ApJ...443....1S, doi:10.1086/175496.
Secrest, Nathan J.; Hausegger, Sebastian von; Rameez, Mohamed; Mohayaee, Roya; Sarkar, Subir; Colin, Jacques (2021-02-25). "A Test of the Cosmological Principle with Quasars". The Astrophysical Journal. 908 (2): L51. arXiv:2009.14826. doi:10.3847/2041-8213/abdd40.
McCrea, W. H.; Milne, E. A. (1934). "Newtonian universes and the curvature of space". Quarterly Journal of Mathematics. 5: 73–80. Bibcode:1934QJMat...5...73M. doi:10.1093/qmath/os-5.1.73
Robertson, H. P. (1935), "Kinematics and world structure", Astrophysical Journal, 82: 284–301, Bibcode:1935ApJ....82..284R
Robertson, H. P. (1936), "Kinematics and world structure II", Astrophysical Journal, 83: 187–201, Bibcode:1936ApJ....83..187R
Robertson, H. P. (1936), "Kinematics and world structure III", Astrophysical Journal, 83: 257–271, Bibcode:1936ApJ....83..257R
Walker, A. G. (1937), "On Milne's theory of world-structure", Proceedings of the London Mathematical Society, Series 2, 42 (1): 90–127, Bibcode:1937PLMS...42...90W
See pp. 351ff. in Hawking, Stephen W.; Ellis, George F. R. (1973), The large scale structure of space-time, Cambridge University Press. The original work is Ehlers, J., Geren, P., Sachs, R.K.: Isotropic solutions of Einstein-Liouville equations. J. Math. Phys. 9, 1344 (1968). For the generalization, see Stoeger, W. R.; Maartens, R; Ellis, George (2007), "Proving Almost-Homogeneity of the Universe: An Almost Ehlers-Geren-Sachs Theorem", Astrophys. J., 39: 1–5, Bibcode:1995ApJ...443....1S, doi:10.1086/175496.
