1. Apanasov, B.: Cusp ends of hyperbolic manifolds. Ann. Glob. Anal. Geom. 3, 1–11 (1985)
2. Apanasov, B.: Conformal Geometry of Discrete Groups and Manifolds. Walter de Gruyter, Germany (2000)
3. Benedetti, R., Petronio, C.: Lectures on Hyperbolic Geometry. Springer, Berlin (2003)
4. Erlandsson, V.: The Margulis region and screw parabolic elements of bounded type. arXiv:1209.5680 . To appear in Bull. Lond. Math. Soc.
5. Erlandsson, V., Zakeri, S.: A discreteness criterion for groups containing parabolic isometries. arXiv:1304.2298 . To appear in Groups, Geometry and Dynamics, Contemp. Math., AMS