Higher-rank graph C*-algebras: an inverse semigroup and groupoid   approach
  We provide inverse semigroup and groupoid models for the Toeplitz and Cuntz-Krieger algebras of finitely aligned higher-rank graphs. Using these models, we prove a uniqueness theorem for the Cuntz-Krieger algebra. 
Cynthia Farthing, Paul S. Muhly, Trent Yeend