@article{PDM_2020_1_a4,
     author = {V. A. Voblyi},
     title = {The number of labeled tetracyclic series-parallel~blocks},
     journal = {Prikladna\^a diskretna\^a matematika},
     pages = {57--61},
     publisher = {mathdoc},
     number = {1},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PDM_2020_1_a4/}
}