@article{CMUC_1978_19_2_a11,
     author = {Poljak, Svatopluk and Turz{\'\i}k, Daniel},
     title = {On amalgamation of graphs and essential sets of generators},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {359--369},
     year = {1978},
     volume = {19},
     number = {2},
     mrnumber = {500128},
     zbl = {0376.05053},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1978_19_2_a11/}
}