@article{RyppaSengeHatscheretal.2005,
  author    = {C. Ryppa and Mathias O. Senge and S. S. Hatscher and Erich Kleinpeter and Philipp Wacker and Uwe Schilde and A. Wiehe},
  title     = {Synthesis of mono- and disubstituted porphyrins : A- and 5,10-A(2)-type systems},
  year      = {2005},
}