@article{oai:ynu.repo.nii.ac.jp:00006988,
 author = {Suzuki, Yusuke and Negami, Seiya},
 issue = {1&2},
 journal = {Yokohama Mathematical Journal = 横濱市立大學紀要. D部門, 数学},
 month = {},
 note = {application/pdf, We shall show that any projective-planar double covering of a 3-connected graph is planar, discussing structures of double covering of planar graphs algebraically and combinatorially.},
 pages = {87--95},
 title = {PROJECTIVE-PLANAR DOUBLE COVERINGS OF 3-CONNECTED GRAPHS},
 volume = {50},
 year = {2003}
}