@article{DMGT_2018_38_2_a0,
     author = {Borowiecki, Mieczys{\l}aw and Drgas-Burchardt, Ewa and Sidorowicz, El\.zbieta},
     title = {\( {\mathcal{P}} {\)-Apex} {Graphs}},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {323--349},
     publisher = {mathdoc},
     volume = {38},
     number = {2},
     year = {2018},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_2018_38_2_a0/}
}