Parameter estimation for the subcritical Heston model based on discrete   time observations
  We study asymptotic properties of some (essentially conditional least squares) parameter estimators for the subcritical Heston model based on discrete time observations derived from conditional least squares estimators of some modified parameters. 
Matyas Barczy, Gyula Pap, Tamas T. Szabo
math.ST math.PR q-fin.ST stat.TH