@article{02148113,
title = {Cooperatie guards in the fortress problem.},
journal = {Balkan Journal of Geometry and its Applications (BJGA)},
volume = {9},
year = {2004},
pages = {103-119},
zbl = {1062.68129},
language = {en},
url = {http://dml.mathdoc.fr/item/02148113}
}
Żyliński, Paweł. Cooperatie guards in the fortress problem.. Balkan Journal of Geometry and its Applications (BJGA), Tome 9 (2004) pp. 103-119. http://gdmltest.u-ga.fr/item/02148113/