TY - JOUR AU - Atapour, Maryam AU - Dehgardi, Nasrin AU - Volkmann, L. TI - An introduction to the twin signed total $k$-domination numbers in directed graphs JO - RAIRO - Operations Research - Recherche Opérationnelle PY - 2017 SP - 1331 EP - 1343 VL - 51 IS - 4 PB - EDP-Sciences UR - http://www.numdam.org/articles/10.1051/ro/2017036/ DO - 10.1051/ro/2017036 LA - en ID - RO_2017__51_4_1331_0 ER -