Theory of Shubnikov--De Haas Oscillations Around the $\nu=1/2$ Filling   Factor of the Landau Level: Effect of Gauge Field Fluctuations
  We present a theory of magnetooscillations around the $\nu =1/2$ Landau level filling factor based on a model with a fluctuating Chern--Simons field. The quasiclassical treatment of the problem is appropriate and leads to an unconventional $\exp\left[-(\pi/\omega_c\tau^*_{1/2})^4\right]$ behavior of the amplitude of oscillations. This result is in good qualitative agreement with available experimental data. 
A.G. Aronov, E. Altshuler, A.D. Mirlin and P. Woelfle