Hubbard, PhD, E. M. The Evolution of Numerical Cognition: From Number Neurons to Linguistic Quantifiers.
Hubbard EM, Diester I, Cantlon JF, Ansari D, Opstal Fv, Troiani V. (2008) The evolution of numerical cognition: from number neurons to linguistic quantifiers. Journal of Neuroscience. Nov 12;28(46):11819-24.