@article{10_1007_s10587_014_0130_9,
     author = {Cho, Jung Rae and Park, Jeongmi and Sano, Yoshio},
     title = {Travel groupoids on infinite graphs},
     journal = {Czechoslovak Mathematical Journal},
     pages = {763--766},
     publisher = {mathdoc},
     volume = {64},
     number = {3},
     year = {2014},
     doi = {10.1007/s10587-014-0130-9},
     mrnumber = {3298558},
     zbl = {06391523},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10587-014-0130-9/}
}