Signed total k -domination numbers of directed graphs. Sheikholeslami, S.M.; Volkmann, L. — 2010 Analele Ştiinţifice ale Universităţii “Ovidius" Constanţa. Seria: Matematică
The diameter of almost Eulerian digraphs. Dankelmann, Peter; Volkmann, L. — 2010 The Electronic Journal of Combinatorics [electronic only]
Signed ( b , k ) -matchings in graphs. Ghameshlou, A.N.; Saei, R.; Sheikholeslami, S.M.; Volkmann, L. — 2010 Analele Ştiinţifice ale Universităţii “Ovidius" Constanţa. Seria: Matematică
Berichtigung zur Arbeit "Über die Charakterisierung der Funktion f(x) = x durch Funktionalgleichungen, II", Band 30 (1986), 142-150. L. Volkmann; P. Volkmann — 1986 Aequationes mathematicae
Signed total distance k -domatic numbers of graphs S. M. Sheikholeslami; L. Volkmann — 2013 Matematički Vesnik