Anisotropy in the Optical Transitions from the π and σ Valence Bands of Graphite Klucker, R. ; Skibowski, M. ; Steinmann, W. Abstract Publication: Physica Status Solidi B Basic Research Pub Date: October 1974 DOI: 10.1002/pssb.2220650230 Bibcode: 1974PSSBR..65..703K