1. LABORATOIRE D'INFORMATIQUE, DE ROBOTIQUE ET DE MICROÉLECTRONIQUE (LIRMM); MONTPELLIER FRANCE
2. FACULTY OF MATHEMATICS, INFORMATICS AND MECHANICS; UNIVERSITY OF WARSAW; WARSAW POLAND
3. UNIVERSITY OF MONTPELLIER; FRANCE
4. DEPARTMENT OF MATHEMATICS; NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS; ATHENS GREECE