Rights:
© 2006 American Physical Society (APS). This is the accepted version of the following article: Leppäkangas, J. & Thuneberg, E. & Lindell, R. & Hakonen, Pertti J. 2006. Tunneling of Cooper pairs across voltage-biased asymmetric single-Cooper-pair transistors. Physical Review B. Volume 74, Issue 5. 054504/1-9. ISSN 1098-0121 (printed). DOI: 10.1103/physrevb.74.054504, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.74.054504.