The Fig. in Ott and Ferrari illustrates the modes and phonon dispersions for a single layer graphene, whereas in the Fig. we can see the Raman spectra of graphite, and pristine and defective graphene. The peaks in the spectra are described in the following manner. "The G peak 1580 cm -1 arises from an E2g phonon stemming from the Γ-point, ... The D peak, corresponding to an A1g phonon ..., is due to the breathing mode of six-atom rings and requires a defect for its activation to fulfill the fundamental Raman selection rule" . This peak is activated by a process involving a transverse optical (TO) phonon at the K point. Similarly, another resonance scattering process at K or K' produces the defectactivated D' peak. The combination D+D' is also present. Peaks 2D and 2D' are the second order modes of D and D', "where the momentum conservation is fulfilled by [the] scattering of two phonons with opposite wave vectors". Consequently, defects are not required for their activation and these peaks "are always present in the Raman spectrum of graphene" . Moreover, the G peak is the only peak in graphene Raman spectrum fulfilling "the fundamental Raman selection rule directly, as its origin is at the center of the Brillouin zone where q = 0" ).