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142                                P. C. EKLUND et al.
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                                                            Japan (1978).
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                                                            (1993).
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             F.  Balkis for help with  computations. One of  the authors   29.  P. Lespade, R. AI-Jishi, and M. S. Dresselhaus, Carbon
              (RAJ) acknowledges AFOSR Grant No. F49620-92-5-0401.   20, 427 (1982).
              The other author (PCE) acknowledges support from Univer-   30.  A. W. Moore, In Chemistry and Physics of Carbon (Ed-
              sity of Kentucky Center for Applied Energy Research and the   ited by P. L. Walker and P. A. Thrower), Vol. 11, p. 69,
              NSF Grant No. EHR-91-08764.                   Marcel Dekker, New York (1973).
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