#### Volume 5, issue 2 (2001)

 1 W Ballmann, Lectures on spaces of nonpositive curvature, DMV Seminar 25, Birkhäuser Verlag (1995) MR1377265 2 W Ballmann, M Brin, Orbihedra of nonpositive curvature, Inst. Hautes Études Sci. Publ. Math. (1995) MR1383216 3 W Ballmann, M Brin, Diameter rigidity of spherical polyhedra, Duke Math. J. 97 (1999) 235 MR1682245 4 M R Bridson, A Haefliger, Metric spaces of non-positive curvature, Grundlehren der Mathematischen Wissenschaften 319, Springer (1999) MR1744486 5 N Bourbaki, Éléments de mathématique, Masson (1981) 290 MR647314 6 K S Brown, Buildings, Springer (1989) MR969123 7 R Charney, M Davis, Singular metrics of nonpositive curvature on branched covers of Riemannian manifolds, Amer. J. Math. 115 (1993) 929 MR1246182 8 , Geometry and cohomology in group theory, London Mathematical Society Lecture Note Series 252, Cambridge University Press (1998) MR1709947 9 M Gromov, Hyperbolic groups, from: "Essays in group theory", Math. Sci. Res. Inst. Publ. 8, Springer (1987) 75 MR919829 10 W M Kantor, Generalized polygons, SCABs and GABs, from: "Buildings and the geometry of diagrams (Como, 1984)", Lecture Notes in Math. 1181, Springer (1986) 79 MR843390 11 B Kleiner, B Leeb, Rigidity of quasi-isometries for symmetric spaces and Euclidean buildings, Inst. Hautes Études Sci. Publ. Math. (1997) MR1608566 12 A Neumaier, Some sporadic geometries related to $\mathrm{PG}(3,2)$, Arch. Math. $($Basel$)$ 42 (1984) 89 MR751477 13 M Ronan, Lectures on buildings, Perspectives in Mathematics 7, Academic Press (1989) MR1005533 14 J Tits, A local approach to buildings, from: "The geometric vein", Springer (1981) 519 MR661801