Wilfried N. Gansterer Computing Orthogonal Decompositions of Block Tridiagonal or Banded Matrices. 25-32 2005 conf/iccS/2005-1 International Conference on Computational Science (1) http://dx.doi.org/10.1007/11428831_4 db/conf/iccS/iccS2005-1.html#Gansterer05