On Low-Energy Effective Action in N=3 Supersymmetric Gauge Theory
  The problem of construction of low-energy effective action in N=3 SYM theory is considered within the harmonic superspace (HSS) approach. The low-energy effective action is supposed to be a gauge- and scale-invariant functional in N=3 HSS reproducing the term F^4/\phi^4 in components. This functional is found as a scale-invariant generalization of the F^4-term in N=3 supersymmetric Born-Infeld action. 
I.B. Samsonov