#### Volume 11, issue 2 (2007)

 1 M Berger, Lectures on geodesics in Riemannian geometry, Tata Institute of Fundamental Research Lectures on Mathematics 33 (1965) MR0215258 2 A L Besse, Manifolds all of whose geodesics are closed, Ergebnisse series 93, Springer (1978) MR496885 3 K S Brown, Buildings, Springer Monographs in Mathematics, Springer (1998) MR1644630 4 K Burns, E Gutkin, Growth of the number of geodesics between points and insecurity for Riemannian manifolds arXiv:math.DS/0701579 5 M W Davis, Buildings are $\mathrm{CAT}(0)$, from: "Geometry and cohomology in group theory (Durham, 1994)", London Math. Soc. Lecture Note Ser. 252, Cambridge Univ. Press (1998) 108 MR1709955 6 M P do Carmo, Riemannian geometry, Mathematics: Theory & Applications, Birkhäuser (1992) MR1138207 7 D Fomin, Zadaqi Leningradskih Matematitcheskih Olimpiad (Leningrad 1990) 8 L W Green, Auf Wiedersehensflächen, Ann. of Math. $(2)$ 78 (1963) 289 MR0155271 9 E Gutkin, Blocking of billiard orbits and security for polygons and flat surfaces, Geom. Funct. Anal. 15 (2005) 83 MR2140629 10 E Gutkin, Insecure configurations in lattice translation surfaces, with applications to polygonal billiards, Discrete Contin. Dyn. Syst. 16 (2006) 367 MR2226486 11 E Gutkin, Blocking of orbits and the phenomenon of (in)security for the billiard in polygons and flat surfaces 12 E Gutkin, V Schroeder, Connecting geodesics and security of configurations in compact locally symmetric spaces, Geom. Dedicata 118 (2006) 185 MR2239456 13 P Hiemer, V Snurnikov, Polygonal billiards with small obstacles, J. Statist. Phys. 90 (1998) 453 MR1611100 14 N D Lebedeva, Spaces without conjugate points and with fundamental group of polynomial growth, Algebra i Analiz 16 (2004) 69 MR2068342 15 R Mañé, On the topological entropy of geodesic flows, J. Differential Geom. 45 (1997) 74 MR1443332 16 T Monteil, A counter-example to the theorem of Hiemer and Snurnikov, J. Statist. Phys. 114 (2004) 1619 MR2039490 17 T Monteil, Finite blocking versus pure periodicity arXiv:math.DS/0406506 18 T Monteil, On the finite blocking property, Ann. Inst. Fourier (Grenoble) 55 (2005) 1195 MR2157167 19 T Monteil, A homological condition for a dynamical and illuminatory classification of torus branched coverings arXiv:math.DS/060335 20 A Nabutovsky, R Rotman, The length of the shortest closed geodesic on a 2-dimensional sphere, Int. Math. Res. Not. (2002) 1211 MR1903953 21 J B Pesin, Formulas for the entropy of the geodesic flow on a compact Riemannian manifold without conjugate points, Mat. Zametki 24 (1978) 553, 591 MR513656 22 S Sabourau, Filling radius and short closed geodesics of the 2-sphere, Bull. Soc. Math. France 132 (2004) 105 MR2075918 23 L A Santaló, Integral geometry in general spaces, from: "Proceedings of the ICM (Cambridge, MA, 1950) Vol. 1", Amer. Math. Soc. (1952) 483 MR0044146 24 J P Serre, Homologie singulière des espaces fibrés. Applications, Ann. of Math. $(2)$ 54 (1951) 425 MR0045386 25 F W Warner, The conjugate locus of a Riemannian manifold, Amer. J. Math. 87 (1965) 575 MR0208534 26 F W Warner, Conjugate loci of constant order, Ann. of Math. $(2)$ 86 (1967) 192 MR0214005 27 O Zoll, Ueber Flächen mit Scharen geschlossener geodätischer Linien, Math. Ann. 57 (1903) 108 MR1511201