Negative Differential Resistance, Oscillations and Constrictions of Low Pressure, Low Current Discharges Z.Lj. Petrovic, I. Stefanovic, S. Vrhovac et J. Zivkovic J. Phys. IV France, 07 C4 (1997) C4-341-C4-352 DOI: 10.1051/jp4:1997428