Versions of SparseM prior to 0.95 included a LICENSE file that described
some uncertainties over the licensing status of the fortran
code in src/cholesky.f. As of 9 March 2012, original authors of cholesky.f,
Esmond Ng and Barry Peyton, have now, very kindly, given permission to
use cholesky.f under an open source license. They have requested that
their code be credited via the following two publications:
Esmond G. Ng and Barry W. Peyton, "Block sparse Cholesky algorithms
on advanced uniprocessor computers". SIAM J. Sci. Stat. Comput.
14 (1993), pp. 1034-1056.
John R. Gilbert, Esmond G. Ng, and Barry W. Peyton, "An efficient
algorithm to compute row and column counts for sparse Cholesky
factorization". SIAM J. Matrix Anal. Appl. 15 (1994), pp. 1075-1091.