@article{Ahrens2003,
  author    = {Ahrens, J.},
  title     = {First measurement of the helicity-dependent gamma p to p eta differential cross-section},
  series = {European Physical Journal},
  journal   = {European Physical Journal},
  number    = {A 17 (2)},
  pages     = {241 -- 244},
  year      = {2003},
  language  = {en}
}
@article{AhrensKiel2003,
  author    = {Ahrens, J. and Kiel, B.},
  title     = {Helicity dependence of the \&\#947;(pol.) p(pol.) \&\#8594; N\&\#960;+\&\#960;0 reaction in the second resonance region},
  series = {Phys. Lett. B551},
  journal   = {Phys. Lett. B551},
  pages     = {49 -- 55},
  year      = {2003},
  language  = {en}
}