Field-emission enhanced breakdown in oxygen microdischarges from direct-current to radio-frequenciesM. Klas, Š. Matejčik, L. Moravsky, B. Radjenović and M. Radmilović-RadjenovićEPL, 120 2 (2017) 25002DOI: https://doi.org/10.1209/0295-5075/120/25002