@article{KYB_1977_13_1_a1,
     author = {Kol\'a\v{r}, Josef},
     title = {A new possibility in bi-directional search},
     journal = {Kybernetika},
     pages = {11--22},
     year = {1977},
     volume = {13},
     number = {1},
     mrnumber = {0449065},
     zbl = {0379.68026},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/KYB_1977_13_1_a1/}
}