build.target            Creates a covariance target, optionally by
                        using prior information (e.g. from KEGG
                        pathways).
expl                    Small example extracted from a microarray data
                        set.
shrink.estim            Shrinkage estimator of the covariance matrix,
                        given a data set and a covariance target.
targetCor               Computation of the target Cor.
targetD                 Computation of the diagonal target D
                        ('diagonal, unequal variances').
targetF                 Computation of target F ('constant correlation
                        model').
targetG                 Computation of target G ('knowledge-based
                        constant correlation model').
targetGpos              Computation of the target Gpos.
targetGstar             Computation of the target Gstar.
