@article{pedersen:2003:vae,
    author = {Pedersen, Thomas G.},
     title = {Variational approach to excitons in carbon nanotubes},
   journal = {Phys. Rev. B},
    volume = {67},
    number = {7},
     pages = {(073401-1)–(073401-4)},
      year = {2003},
       doi = {10.1103/PhysRevB.67.073401},
 publisher = {American Physical Society}}