1. Berry, M. (1989). Principles of cosmology and gravitation. Adam Hilger.
2. Blondin, S., Davis, T. M., Krisciunas, K., et al. (2008). Time dilation in Type Ia supernova spectra at high redshift. The Astrophysical Journal, 682(2), 724–736. https://doi.org/10.1086/589568.
3. Bolyai, J. (1832). Appendix: Scientiam spatii absolute veritam exhibens (Appendix: Explaining the absolutely true science of space). An attempt to introduce studious youth to the elements of pure mathematics. Maros Vásárhely. Published as an appendix to the essay by his father F. Bolyai.
4. Bondi, H. (1960). Cosmology (2nd ed.). Cambridge University Press.
5. Einstein, A. (1917). Kosmologische Betrachtungen zur Allgemeinen Relativitätstheorie (Cosmological Considerations in the General Theory of Relativity). Sitzungsberichte, Königlich Preussische Akademie der Wissenschaften, I, 142–152.