No-counterexample interpretation et sp\'{e}cification des   th\'{e}or\`{e}mes de l'arithm\'{e}tique
  This paper presents two different ways of extracting the computational content of formal proofs in arithmetic. The first one corresponds to Kreisel's No-counterexample Interpretation. based on Ackermann consistency proof. We show the link with recent work by Krivine on classical realizability. Finally, we discuss the various degrees of modularity of both approaches. 
Denis Bonnay (PPS)