Comment on ``Observation of the $\nu=1$ quantum Hall effect in a   strongly localized two-dimensional system''
  In a recent Rapid Communication ``Observation of the $\nu=1$ quantum Hall effect in a strongly localized two-dimensional system,'' Shahar, Tsui, and Cunningham reported a disorder --- magnetic field phase diagram for the integer quantum Hall effect that appeared to differ qualitatively from theoretical predictions as well as from experimental results obtained by others. In this Comment, I suggest a possible origin of this difference. 
S. V. Kravchenko (Department of Physics, City College of the City   University of New York, New York, New York)