@article{cs-svdtf-11
,   author =     "Colin de Verdi{\`e}re, {\'E}ric and Schrijver, Alexander"
,   title =      "Shortest vertex-disjoint two-face paths in planar graphs"
, journal = "ACM Transactions on Algorithms"
,   year =       2011
, volume = 7
, number = 2
, pages = "Article~19"
}