USSR physicists intensively elaborated the methods
for solving nonlinear problems.
The spring VII School on Nonlinear Waves was in Nizhnii Novgorod region
on March 21-30 , 1985.
Program: from March 21, 1985 - till Mach 30, 1985 .
This resulted in my articles on :
dynamical chaos in multimode laser
see JOSA B, v.3, n.5, 1986
filamentation of laser beam in gain medium
see Quantum Electronics, v.18, n.2, 1988