@article{RO_2020__54_4_1027_0,
     author = {Mojdeh, Doost Ali and Samadi, Babak and Yero, Ismael G.},
     title = {Global defensive $k$-alliances in directed graphs: combinatorial and computational issues},
     journal = {RAIRO - Operations Research - Recherche Op\'erationnelle},
     pages = {1027--1040},
     publisher = {EDP-Sciences},
     volume = {54},
     number = {4},
     year = {2020},
     doi = {10.1051/ro/2019049},
     mrnumber = {4100699},
     language = {en},
     url = {http://archive.numdam.org/articles/10.1051/ro/2019049/}
}