@article{JGAA_2017_21_5_a6,
     author = {\'Eric Colin de Verdi\`ere and Vojt\v{e}ch Kalu\v{z}a and Pavel Pat\'ak and Zuzana Pat\'akov\'a and Martin Tancer},
     title = {A {Direct} {Proof} of the {Strong} {Hanani-Tutte} {Theorem} on the {Projective} {Plane}},
     journal = {Journal of Graph Algorithms and Applications},
     pages = {939--981},
     publisher = {mathdoc},
     volume = {21},
     number = {5},
     year = {2017},
     doi = {10.7155/jgaa.00445},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.7155/jgaa.00445/}
}