@article{10_21136_CPM_1981_108493,
     author = {Zelinka, Bohdan},
     title = {Graphs of semigroups},
     journal = {\v{C}asopis pro p\v{e}stov\'an{\'\i} matematiky},
     pages = {407--408},
     publisher = {mathdoc},
     volume = {106},
     number = {4},
     year = {1981},
     doi = {10.21136/CPM.1981.108493},
     mrnumber = {637820},
     zbl = {0479.05033},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CPM.1981.108493/}
}