Martin Maechler, based on S original by Peter Rousseeuw <rousse@uia.ua.ac.be>,
Anja.Struyf@uia.ua.ac.be and Mia.Hubert@uia.ua.ac.be,
and initial R port by Kurt.Hornik@R-project.org
Cluster Analysis Extended Rousseeuw et al.
Cluster Analysis, extended original from
Peter Rousseeuw, Anja Struyf and Mia Hubert.