B. Awerbuch, M. Betke, R. L. Rivest, and M. Singh, Piecemeal Graph Exploration by a Mobile Robot, Information and Computation, vol.152, issue.2, pp.155-172, 1999.
DOI : 10.1006/inco.1999.2795

P. Brass, F. Cabrera-mora, A. Gasparri, and J. Xiao, Multirobot Tree and Graph Exploration, IEEE Transactions on Robotics, vol.27, issue.4, pp.707-717, 2011.
DOI : 10.1109/TRO.2011.2121170

J. Czyzowicz, D. Ilcinkas, A. Labourel, and A. Pelc, Optimal Exploration of Terrains with Obstacles, Proc. 12 th Scandinavian Symp. and Workshops on Algorithm Theory (SWAT), pp.1-12, 2010.
DOI : 10.1007/978-3-642-13731-0_1

URL : https://hal.archives-ouvertes.fr/hal-00516061

C. A. Duncan, S. G. Kobourov, and V. S. Kumar, Optimal constrained graph exploration, ACM Transactions on Algorithms, vol.2, issue.3, pp.380-402, 2006.
DOI : 10.1145/1159892.1159897

M. Dynia, M. Korzeniowski, and C. Schindelhauer, Power-Aware Collective Tree Exploration, Proc. 19 th Int. Conf. on Architecture of Computing Systems (ARCS), pp.341-351, 2006.
DOI : 10.1007/11682127_24

URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.86.2100

M. Dynia, J. Kuty?owski, F. Meyer-auf-der-heide, and C. Schindelhauer, Smart Robot Teams Exploring Sparse Trees, Proc. 31 st Int. Symp. on Mathematical Foundations of Computer Science (MFCS), pp.327-338, 2006.
DOI : 10.1007/11821069_29

M. Dynia, J. ?opusza?ski, and C. Schindelhauer, Why Robots Need Maps, Proc. 14 th Int. Colloq . on Structural Information and Communication Complexity (SIROCCO), pp.41-50, 2007.
DOI : 10.1007/978-3-540-72951-8_5

P. Fraigniaud, L. G¸asieniecg¸asieniec, D. R. Kowalski, and A. Pelc, Collective tree exploration, Networks, vol.36, issue.3, pp.166-177, 2006.
DOI : 10.1002/net.20127

G. N. Frederickson, M. S. Hecht, and C. E. Kim, Approximation Algorithms for Some Routing Problems, SIAM Journal on Computing, vol.7, issue.2, pp.178-193, 1978.
DOI : 10.1137/0207017

Y. Gabriely and E. Rimon, Competitive on-line coverage of grid environments by a mobile robot, Computational Geometry, vol.24, issue.3, pp.197-224, 2003.
DOI : 10.1016/S0925-7721(02)00110-4

D. Herrmann, T. Kamphans, and E. Langetepe, Exploring simple triangular and hexagonal grid polygons online. CoRR, abs/1012, 2010.

Y. Higashikawa and N. Katoh, Online Exploration of All Vertices in a Simple Polygon, Proc. 6 th Frontiers in Algorithmics Workshop and the 8 th Int. Conf. on Algorithmic Aspects of Information and Management (FAW-AAIM), pp.315-326, 2012.
DOI : 10.1007/978-3-642-29700-7_29

Y. Higashikawa, N. Katoh, S. Langerman, and S. Tanigawa, Online graph exploration algorithms for cycles and trees by multiple searchers, Journal of Combinatorial Optimization, vol.33, issue.2, 2013.
DOI : 10.1007/s10878-012-9571-y

C. Icking, T. Kamphans, R. Klein, and E. Langetepe, Exploring an unknown cellular environment, Proc. 16 th European Workshop on Computational Geometry (EuroCG), pp.140-143, 2000.

A. Kolenderska, A. Kosowski, M. Malafiejski, and P. ?yli?ski, An Improved Strategy for Exploring a Grid Polygon, Proc. 16 th Int. Colloq. on Structural Information and Communication Complexity (SIROCCO), pp.222-236, 2009.
DOI : 10.1137/S0097539796309764

J. ?opusza?ski, Tree exploration (in Polish), 2007.

C. Ortolf and C. Schindelhauer, Online multi-robot exploration of grid graphs with rectangular obstacles, Proceedinbgs of the 24th ACM symposium on Parallelism in algorithms and architectures, SPAA '12, pp.27-36, 2012.
DOI : 10.1145/2312005.2312010