@article{10_4153_CJM_1966_080_9,
     author = {Robkin, Eugene and Valentine, F. A.},
     title = {Parallel {Lines} {Associated} with {Two} {Sets}},
     journal = {Canadian journal of mathematics},
     pages = {811--816},
     year = {1966},
     volume = {18},
     number = {1},
     doi = {10.4153/CJM-1966-080-9},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1966-080-9/}
}