@article{10_2140_agt_2009_9_549,
     author = {Dydak, Jerzy and Levin, Michael},
     title = {Maps to the projective plane},
     journal = {Algebraic and Geometric Topology},
     pages = {549--568},
     year = {2009},
     volume = {9},
     number = {1},
     doi = {10.2140/agt.2009.9.549},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2009.9.549/}
}