Commensurability classes of 2-bridge knot complements
  We show that a hyperbolic 2-bridge knot complement is the unique knot complement in its commensurability class. We also discuss constructions of commensurable hyperbolic knot complements and put forth a conjecture on the number of hyperbolic knot complements in a commensurability class. 
Alan W. Reid and Genevieve S. Walsh