@InProceedings{Sch07,
  title     = {Analysing periodic phenomena by circular {PCA}},
  booktitle = {Proceedings {BIRD} conference},
  editor    = {M.~Hochreiter and R.~Wagner},
  pages     = {38--47} ,
  publisher = {Springer-Verlag Berlin Heidelberg},
  series    = {LNCS/LNBI 4414},
  year      = {2007}
}