@article{MS2_1981__48_166748,
     author = {F. Harary and G. Exoo and J. Kabell},
     title = {The crossing numbers of some generalized {Petersen} graphs.},
     journal = {Mathematica Scandinavica},
     pages = {184--188},
     year = {1981},
     volume = {48},
     zbl = {0442.05021},
     url = {http://geodesic.mathdoc.fr/item/MS2_1981__48_166748/}
}