In the article by Wieligor and coworkers, it follows a detailed discussion about Brillouin zone activity in the first-order Raman scattering and about the grain size effect, concluding that, "in view of the discussion of the TO band position dependence on effects other than the crystal size, it is reasonable to assume that the LO band is also affected by the presence of defects, strains and surface layer, and the observed frequency shift cannot be used to evaluate grain sizes. The existence of defects is also manifested by large band widths and the presence of shoulders" .