1. Nets and groups;Baer;Trans. Amer. Math. Soc.,1939
2. J. Baez, Torsor made easy, http://math.ucr.edu/home/baez/torsors.html, 2009.
3. J.M. Beck, Triples, algebras and cohomology, Ph.D. dissertation, Columbia University, 1964.
4. N. Bourbaki, Algèbre: Chapitres 1 à 3, Masson, Paris, 1970.
5. Contributions to the theory of loops;Bruck;Trans. Amer. Math. Soc.,1946