The Semiclassical Propagator for Spin Coherent States
  We use a continuous-time path integral to obtain the semiclassical propagator for minimal-spread spin coherent states. We pay particular attention to the ``extra phase'' discovered by Solari and Kochetov, and show that this correction is related to an anomaly in the fluctuation determinant. We show that, once this extra factor is included, the semiclassical propagator has the correct short time behaviour to $O(T^2)$, and demonstrate its consistency under dissection of the path 
Michael Stone, Kee-Su Park, Anupam Garg