A multi-phase Mullins-Sekerka system matched asymptotic expansions and an implicit time discretization for the geometric evolution problem - Bronsard, Lia; Garcke, Harald; Stoth, Barbara ([Preprint] / Rheinische Friedrich-Wilhelms-Universität Bonn, Sonderforschungsbereich 256, Nichtlineare Partielle Differentialgleichungen, 1996)