On two-dimensional immersions of prescribed mean curvature in R^n
  We consider two-dimensional immersions of disc-type in R^n. We focus well known classical concepts and study the nonlinear elliptic systems of such mappings. Using an Osserman-type condition we give a priori-estimates of the principle curvatures for certain graphs in R^4 with prescribed mean curvature. 
Matthias Bergner, Steffen Froehlich