homepages/83/24,
Bonnie S. Heck-Ferri and Bonnie S. Heck, Home Page, http://www.ece.gatech.edu/personnel/publications.php?id=47, Georgia Institute of Technology, Atlanta, USA
homepages/03/9961,
Christina Robenek and Christina Otte, Home Page, http://www.informatik.uni-kiel.de/theorie-der-parallelitaet/mitarbeiter/cot/, University of Kiel, Germany
homepages/84/8513,
Lars Dannecker, Home Page, http://wwwdb.inf.tu-dresden.de/team/external-members/dipl-medien-inf-lars-dannecker/, Dresden University of Technology, Germany
homepages/84/183,
Peter Michael Young, Home Page, http://www.engr.colostate.edu/ece/facultystaff/facultypage.cfm?pass=21, Colorado State University, USA