  We start with a Riemann-Hilbert Problems (RHP) with canonical normalization
whose sewing functions depends on several additional variables. Using
Zakharov-Shabat theorem we are able to construct a family of ordinary
differential operators for which the solution of the RHP is a common
fundamental analytic solution. This family of operators obviously commute. Thus
we are able to construct new classes of integrable nonlinear evolution
equations.
