by I.S. Krasil'shchik and M. Marvan
Acta Appl. Math. 56 (1999) 217–230.
LANL preprint
We insert the spectral parameter into the Gauss-Mainardi-Codazzi equations in Tchebycheff and geodesic coordinates. For each choice, four integrable systems are obtained. Computation relies on results of On zero curvature representations of partial differential equations.