@article{10_21136_MB_2002_133957,
     author = {Zhang, Ping},
     title = {On $k$-strong distance in strong digraphs},
     journal = {Mathematica Bohemica},
     pages = {557--570},
     publisher = {mathdoc},
     volume = {127},
     number = {4},
     year = {2002},
     doi = {10.21136/MB.2002.133957},
     mrnumber = {1942641},
     zbl = {1003.05037},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/MB.2002.133957/}
}