@article{ARM_1968__4_2_a2,
     author = {Skula, Ladislav},
     title = {Prime elements in the semigroup of finite types of partially ordered sets in cardinal multiplication},
     journal = {Archivum mathematicum},
     pages = {97--101},
     publisher = {mathdoc},
     volume = {04},
     number = {2},
     year = {1968},
     mrnumber = {0277441},
     zbl = {0208.28904},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1968__4_2_a2/}
}