Projective Superspace as a Double--Punctured Harmonic Superspace
  We analyse the relationship between the N=2 harmonic and projective superspaces which are the only approaches developed to describe general N=2 super Yang-Mills theories in terms of off-shell supermultiplets with conventional supersymmetry. The structure of low-energy hypermultiplet effective action is briefly discussed. 
Sergei M. Kuzenko