@article{NSJOM_2004_34_2a_1,
     author = {M. Bogdanovi\'c and S. Bogdanovi\'c and T. Petkovi\'c and M. \'Ciri\'c},
     title = {Necks of 

 automata},
     journal = {Novi Sad Journal of Mathematics},
     pages = {5-15},
     publisher = {mathdoc},
     volume = {34},
     number = {2},
     year = {2004},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_2004_34_2a_1/}
}