The Helmholtz conditions for the difference equations systems. Crăciun, Dumitru; Opriş, Dumitru — 1996 Balkan Journal of Geometry and its Applications (BJGA)
Discrete-continuous systems with symmetry. Crăciun, Dana; Opriş, Dumitru — 1997 Balkan Journal of Geometry and its Applications (BJGA)
Helmholtz type condition for mechanical integrators. Albu, Ion D.; Opris, Dumitru — 1999 Novi Sad Journal of Mathematics
The Maxwell-Bloch equations on fractional Leibniz algebroids. Ivan, Mihai; Ivan, Gheorge; Opriş, Dumitru — 2008 Balkan Journal of Geometry and its Applications (BJGA)