@article{10_37236_2414,
     author = {Ville Junnila and Tero Laihonen},
     title = {Optimal lower bound for 2-identifying codes in the hexagonal grid},
     journal = {The electronic journal of combinatorics},
     year = {2012},
     volume = {19},
     number = {2},
     doi = {10.37236/2414},
     zbl = {1252.05177},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/2414/}
}