#### Volume 13, issue 2 (2009)

 1 W Ballmann, Lectures on spaces of nonpositive curvature, DMV Seminar 25, Birkhäuser Verlag (1995) MR1377265 2 C Druţu, M Sapir, Tree-graded spaces and asymptotic cones of groups, Topology 44 (2005) 959 MR2153979 3 M A Hindawi, Large scale geometry of $4$–dimensional closed nonpositively curved real analytic manifolds, Int. Math. Res. Not. (2005) 1803 MR2172938 4 G C Hruska, B Kleiner, Hadamard spaces with isolated flats, Geom. Topol. 9 (2005) 1501 MR2175151