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Article History
Received: 25 July 2015
Accepted: 11 September 2015
First Online: 4 November 2015
Change Date: 18 November 2015
Change Type: Correction
Change Details: In the Methods, the equation for the equal-time reduced Bethe-Salpeter amplitude (which can be approximated by the outer solution of the scattering problem) was corrected.
Competing interests
: The author declare no competing financial interests.