Optimized fast algorithms for the quaternionic Fourier transform
@InProceedings{felsberg99caip,
  author = 	 {M. Felsberg and G. Sommer},
  title = 	 {Optimized fast algorithms for the quaternionic {F}ourier transform},
  booktitle = 	 {8th Int. Conference on Computer Analysis of Images and Patterns, Ljubljana},
  year =	 1999,
  publisher =	 {Springer-Verlag},
  editor =       {F. Solina and A. Leonardis},
  series =       {LNCS},
  volume =       1689,
  pages =	 {209-216},
  }