C^1 Hypersurfaces of the Heisenberg Group are N-Rectifiable
  We show that C^1 hypersurfaces in the Heisenberg group are countably N-rectifiable. As a corollary, this shows that all C^1_H graphs over the xy-plane are countable N-rectifiable, showing the equivalence of this notion of rectifiability with that of Franchi, Serra Cassano and Serapioni for such surfaces. 
Daniel R. Cole, Scott D. Pauls