2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/161867We review harmonic superspaces of the D=3, N=3 and 4 supersymmetries and gauge models in these superspaces. Superspaces of the D=3, N=5 supersymmetry use harmonic coordinates of the SO(5) group. The superfield N=5 actions describe the off-shell infinite-dimensional Chern-Simons supermultiplet.The contribution to Tomsk volume dedicated to 60th birthday of professor I.I. BuchbinderHigh Energy Physics - Theorytext