Discretized representations of harmonic variables by bilateral Jacobi operators. Ruffing, Andreas — 2000 Discrete Dynamics in Nature and Society
Differential representations of dynamical oscillator symmetries in discrete Hilbert space. Ruffing, Andreas — 2000 Discrete Dynamics in Nature and Society
Power series techniques for a special Schrödinger operator and related difference equations. Simon, Moritz; Ruffing, Andreas — 2005 Advances in Difference Equations [electronic only]
Using supermodels in quantum optics. Garbers, Nicole; Ruffing, Andreas — 2006 Advances in Difference Equations [electronic only]