Shear and Layer Breathing Modes in Multilayer MoS2
  We study by Raman scattering the shear and layer breathing modes in multilayer MoS2. These are identified by polarization measurements and symmetry analysis. Their positions change with the number of layers, with different scaling for odd and even layers. A chain model explains the results, with general applicability to any layered material, and allows one to monitor their thickness. 
X. Zhang, W. P. Han, J. B. Wu, S. Milana, Y. Lu, Q. Q. Li, A. C.   Ferrari, P. H. Tan
cond-mat.mes-hall cond-mat.mtrl-sci