By Gerhard Wanner
Also appears in collections : Special events, Lagrange Days
By Olivier Darrigol
By Jean-Claude Saut
By Volker Mehrmann
By Bruno Després
By Emmanuel Trélat
By Dmitry Treschev
By Norbert Verdier
By Albert Schwarz
By Aaron Brown
By Victor Kleptsyn
By Stephen Coombes , Peter Liddle
By Jean Feydy