Claudio Moraga Radomir S. Stankovic Jaakko Astola Properties of matrix-valued spectral coefficients obtained with the Fourier Transform on a non-Abelian group. 35 2006 conf/ismvl/2006 ISMVL http://doi.ieeecomputersociety.org/10.1109/ISMVL.2006.34 db/conf/ismvl/ismvl2006.html#MoragaSA06