@article{JGAA_2003_7_2_a6,
     author = {Walter Didimo and Maurizio Pizzonia},
     title = {Upward {Embeddings} and {Orientations} of {Undirected} {Planar} {Graphs}},
     journal = {Journal of Graph Algorithms and Applications},
     pages = {221--241},
     publisher = {mathdoc},
     volume = {7},
     number = {2},
     year = {2003},
     doi = {10.7155/jgaa.00068},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.7155/jgaa.00068/}
}