t-Lead: Tripolar Concentric Ring Electrode (TCRE)-based sensor » Brain Vision
Medical BCI Researcher AG/AgCl EEG Reference Ring Electrodes - China Sintered Ring Electrode, Sintered AG/Agcl | Made-in-China.com
Solving the general inter-ring distances optimization problem for concentric ring electrodes to improve Laplacian estimation | BioMedical Engineering OnLine | Full Text