References
- L. V. Sabinin, L. L. Sabinin, and L. V. Sbitneva, On the notion of a gyrogroup, Aequ. Math., 56(1998), 11-17. https://doi.org/10.1007/s000100050039
- A. A. Ungar, Analytic hyperbolic geometry and Albert Einstein's special theory of relativity, World Scientific Press, 2008.