Gromov hyperbolic space

References

• Bowditch, Brian (2006), A course on geometric group theory, Mat. soc. Japan
• Bridson, Martin R.; Haefliger, André (1999), Metric spaces of non-positive curvature, Springer
• Coornaert, M.; Delzant, T.; Papadopoulos, A. (1990), Géométrie et théorie des groupes. Les groupes hyperboliques de Gromov, Lecture Notes in Mathematics (in French), vol. 1441, Springer-Verlag, ISBN 
• de la Harpe, Pierre; Ghys, Etienne (1990), Sur les groupes hyperboliques d'après Mikhael Gromov (in French), Birkhäuser
• Gromov, Mikhael (1987), "Hyperbolic groups", in Gersten, S.M. (ed.), Essays in group theory, Springer, pp. 75–264
• Roe, John (2003), Lectures on Coarse Geometry, University Lecture Series, vol. 31, American Mathematical Society, ISBN 
• Väisälä, Jussi (2005), "Gromov hyperbolic spaces", Expositiones Mathematicae, 23 (3): 187–231, doi:10.1016/j.exmath.2005.01.010, MR 2164775.