Cord-Landwehr, A., Degener, B., Fischer, M., Hüllmann, M., Kempkes, B., Klaas, A.,https://doi.org/10.1007/978-3-642-18381-2_15__Wonisch, D. (2011). Collisionless Gathering of Robots with an Extent. In SOFSEM 2011: Theory and Practice of Computer Science. Berlin, Heidelberg.https://doi.org/10.1007/978-3-642-18381-2_15 

Cord-Landwehr, A., Degener, B., Fischer, M., Hüllmann, M., Kempkes, B., Klaas, A.,https://doi.org/10.1007/978-3-642-18381-2_15__Wonisch, D. (2011). Collisionless Gathering of Robots with an Extent. In 37th International Conference on Current Trends in Theory and Practice of Computer Science (SOFSEM 2011) (pp. 178–189). Springer.https://doi.org/10.1007/978-3-642-18381-2_15