Rights:
© 2007 American Physical Society (APS). This is the accepted version of the following article: Krasheninnikov, A. V. & Foster, Adam S. & Nieminen, R. M.. 2007. Comment on 'Paired Gap States in a Semiconducting Carbon Nanotube: Deep and Shallow Levels'. Physical Review Letters. Volume 99, Issue 17. 179703/1. ISSN 0031-9007 (printed). DOI: 10.1103/physrevlett.99.179703, which has been published in final form at http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.99.179703.