@article{10_21136_AM_1980_103883,
     author = {Plesn{\'\i}k, J\'an},
     title = {On the computational complexity of centers locating in a graph},
     journal = {Applications of Mathematics},
     pages = {445--452},
     publisher = {mathdoc},
     volume = {25},
     number = {6},
     year = {1980},
     doi = {10.21136/AM.1980.103883},
     mrnumber = {0596851},
     zbl = {0454.68026},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/AM.1980.103883/}
}